I think you will find the flowers are wall decals. https://www.etsy.com/listing/517922486/soft-pink-peony-wall-decal-set-made-from?ref=pla_sameshop_listing_top-2&pro=1&frs=1 https://www.etsy.com/listing/538206843/peel-and-stick-wallpaper-mural-decals?ref=listing_page_ad_row-1&plkey=74ef56f1339295cf17ef4fc701cae8c81c47f393%3A538206843&pro=1&frs=1 https://www.etsy.com/listing/742549136/dark-floral-wallpaper-removable-peel-and?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=large+flower+wall+decal&ref=sr_gallery-1-21&frs=1 https://www.etsy.com/listing/789510345/floral-wallpaper-peel-and-stick-self?ref=related-2&frs=1 https://www.etsy.com/search?q=Dark%20Dutch%20Oil%20Paint%20Mural%20flower%20adhesive%20mural https://www.etsy.com/listing/901110421/dutch-floral-vinyl-wallpaper-botanical?ref=related-2&frs=1

I do not want to be a PITA but I would not do a childs room with wall paper so maybe a bit of info as to the age of the child. I find the best is to keep the walls neutral and add decals or maybe a bit of dry strippable wall paper on a small area since kids favorite colors change yearly when the are young. and removing expensive wall paper is not a great idea.I have 2 grand daughters and of course becasue I am a designer I had the pleasure of doing their rooms as the grew up and boy I sure would not have done wallpaper and for sure not such a busy one.

Sure, here it is … the name of it is Shaan: In a lighter color, looks like yours. it came in various colors, both flowers and background … Home Depot, Lowes, Ama-zon, etc used to sell it, but all are saying out of stock. Hope you can find it!

You should have used an oil based primer. Peel off what has now loosened and bubbled up, and resand it smooth as you can get it, and prime it all over again with oil based primer. Once the primer is good and dry, you can paint it with latex paint. It would be a good thing to put on two coats of oil based primer, just to make sure it is well sealed. However, if you get a good first coat and are not missing any spots, you can probably get by with 1 coat of primer.