Permanent would be to cut out the loose area, re mud and feather in and rematch the texture. You've done repairs and texture matching in the past, so you might as well do it right. The syringe/water will only weaken it.

I do not claim to be a drywall expert-- but I have done lots of small-scale drywall work. If this was mine, I would select an area that is not seen much-- inside a closet is ideal- and experiment. Try 3 or 4 spots with each technique. The loose stuff must be removed first so that any added material is bonded to firm surfaces. Brush away any dust from that area. One technique is drywall compound alone, thin layers. Another is to use Gorilla glue in the spot, just enough to wet out the area by spreading it with a dull table knife and immediately cover it with a larger piece of blue masking tape. Leave the tape for 24 hours, peel it off, sand flush, then drywall compound over that and sand smooth again. The glue foams up and sands well after fully dried-- but leaves a porous surface. It holds tenaciously to both paper and the gypsum core. Admission: I have not tried the Gorilla glue for this problem- but I certainly would if I had the problem you describe. The adhesive on the tape should act as a release agent from the cured Gorilla glue. If it does not, paint thinner will gradually loosen the rubber-based adhesive on the tape. Prime all repaired spots, let the primer dry and sand lightly before finish paint. I prefer oil base primer for sealing these patches, but it is virtually unavailable now. Be imaginative and dream up additional things to try. Bondo auto body filler? This post was edited by bus_driver on Sat, Apr 13, 13 at 13:49

I'm having a difficult time seeing water damage there. Reason? Water flows down---not in horizontal layers. Try using a hat pin---the long straight pins with a ball handle end. Poke it through a point above the bubbles and then through the center of a bubble. If there is water damage, the resistance will be less. If both areas feel the same, I'd bet the paint bubbled the drywall or the previous layer of paint.

I didn't realize I was providing the information piecemeal - that wasn't my intention so apologies for that. So let me start from the beginning. The house is 22 years old. I bought the house in Jul 2016 - I'm the 5th owner. In 2012, one of the previous owners had the shingles redone - I have the receipt for that. Since owning the house I have seen brown droplets on the ceiling of the skylight opening and on the baseboard below the skylight. At first I didn't notice it, and then I ignored but when I realize that the problem wasn't going away and that there were drip stains in the skylight I inquired. I've never seen actually wet raindrops - it's always dried on the wall, ceilings and baseboard. I was told by a friend that I should speak to a roofer so I contacted the roofer who did roof in Nov 2012. The first time he came he asked who did the roof, I said you guys - he said well it should be covered under warranty. Second time he came, before even going on the roof he said I already know what the problem is - it's the flashing and shingling. He went on the roof and took those exterior pictures and confirmed what he said - that it was poorly installed. He said he would talk to his boss and see what they can do for me. Then the office manager got involved as soon as he left and started saying they didn't install the skylight - it's not their responsibility, not under warranty. I said the skylight was installed before the roof so they should have ensured it was water tight but they claimed the skylight was after they did the roof. He said "there's no way the skylight is 7 years old - it hasn't even weathered" - he was angry and rude, shouting at me. Let's call him contractor A. I asked the previous owners (who I'm friends with), if they knew anything about the skylight - they said the didn't touch while they lived in the house. So I asked contract A for proof that he skylight was installed after the roof and he got mad - I ended up hanging up on him because he was shouting at me. I figured - I was out of luck so I got a referral from a friend who is contractor and made an appointment with him - let's call him contractor B. A few days later contractor A emails asking if he can take a picture of the stamp on the window. I said sure and gave him some times when I was home - he shows up with some other guys and start showing me pics on the phone ...one day when I wasn't home, he trespassed onto my property without my permission or knowledge, and took pictures! He did apologize but how can you trust someone like that. He then proceeded to say that stamp shows 2012 and claimed that the previous owner in question must've had the skylight installed after roof "because there's no way we did that" and was talking about the size of the shingles and the condition of the flashing, etc. He also said the warranty is with the previous owner, not me. To me, it still didn't prove the skylight was installed after - why would the previous owner get a new skylight after getting the roof done a couple of weeks later, in the winter just before xmas? Anyways, he offered to fix the problem for half price (half of $800 - $400). He wanted to do it right away - the next day (Saturday). I said let me think about it (I had contractor B coming over to give me a quote later that day). Contractor B came and first looked at the interior and suggested insulating/vapour barrier. Then went outside (didn't not go on the roof - it's a very steep roof and it was raining that day) and said the flashing and shingling around the skylight needed to be fixed. He emailed me a quote $435 for the exterior work, $350 for the interior. I copied and pasted the work he detailed from the quote. So then I came on here asking is the interior work needed. That's all the information I have. I don't understand the comment about me being happy. I thought I asked a very simple question - All I was trying to find out was insulation is necessary and I still don't know the answer to that. I'm so confused and overwhelmed with all the conflicting information I have received - I don't know who to believe or what's what. If anyone has read this long posts and can help me out - it would be appreciated.