You can try thinners (cellulose) or some other, but I think your done for, once it sets, it has to wear off! Hope your not a doctor. One way I've got it off, is with a pan scourer (scotchbrite type pad) and washing up liquid, it's a long job and there wont be a lot of skin left, so be careful!!
Yes, this is good advice. Polyurethane thinners work well enough, but leaves your hands feeling really nasty, and can't do any good to your skin. This is only for if you have to give a major business presentation tomorrow.
Better is to leave it for a few hours to go off , then scrub off the worst with a green "Scotchbrite" scourer and hot soapy water. Rub your fingers together for the rest of the evening and the remainder will gradually 'ball up' and clear. But expect some residue for a day or two.
One consolation, look at the strap-hangers Monday mornings this time of year, you'll be surprised at the number of people with odd-tinted digits. And in future, borrow 'er indoors' Marigolds.
I've just been completing a fibreglass repair on my hull and I used these disposable gloves from my local decorator shop (10p/pair). They are great, fit perfectly and you just throw them away once used. Unfortunately once I'd done that, I returned 30 mins later to check the clamp and leaned on a tyre stack that is propping up the boat. The resin had dripped onto the top tyre and then efficiently transferred itself onto my arm. This I discovered a few minutes later when I touched it with my left hand which, of course, then also got covered in resin. To top it off I discovered that I had no thinners on site. I must have looked a right pratt driving back wearing these disposable, condom-like gloves.
You could ruin SWMBO's marigolds but just think how much she will spend while she is buying a replacement pair.
Sikaflex seems to dissolve in contact with pure detergent. Also usefull for the finishing touch. Simply apply copious amounts of detergent to your finger and go over the sika line. Et voila: a smooth concave finish.