It looks like a tobacco budworm to me. These caterpillars come in many colors, and, according to David Wagner, they 'end up matching the color of their foodplant' so I'm guessing this one has been eating another flower before it traveled to the pink hibiscus. Or maybe it was eating deep inside the bud where it was pale green. These caterpillars are closely related to the familiar corn earworm. Cotton is second in the list of common food plants, and cotton and hibiscus are in the same family of plants, so it figures. I've never raised any gray hairstreaks, so I had to look them up, too, in my Wagner book. He didn't say whether they ONLY eat flowers, but he says that's where to look for them, and the picture in the book is of a cat on a flower. The mallow family is listed second as a favorite food plant, and hibiscus and cotton are in that family. I assume they eat flowers exclusively, but I'd offer it some leaves, just in case. Nice finds! Sherry

I am so sorry this happened. You'll never forget about this chance meeting, will you? Some caterpillar stings are terribly painful and can cause severe reactions. Are you hypersensitive to other insect 'bodily fluids' such as those from ants, mosquitoes and the like? My own experience was with the Saddleback caterpillar. I thought that I had been shot when my arm brushed against the stinging hairs. The bad thing about the buckmoth caterpillar is that they are often found in numbers. So be watchful. Wear gloves. Keep some meat tenderizer with you when working outside. Make a paste of the granules to apply directly to the site right after you've been stung. It will help. Purchase some benadryl to keep on hand for such incidents, both oral and topical. I've seen people develop what looks like broken blood vessels where the spines entered the skin. Took several days for the whole thing to clear up and go away. Tell us how you are doing!

I know the second one as the Puss caterpillar, Megalopyge opercularis. I've heard that their sting is more painful than that from a Saddleback, which I am personally familiar with. Yikes! For insect cuteness, look at the Puss moth.....talk about cute and cuddly.

Thank you @gardengal48 and @rhizo_1 for the suggestions. I'm off to go track some down right now. I was hoping a mixture of dish soap and/or chili peppers (something along those lines) might work so I don't have to go purchase. Once you start gardening, then the "supplies" start to really accrue over time! ;)