If you are working indoors, buy yourself a good organic or fresh air mask to wear while you're working. You can buy organic and fresh air masks at most automotive paint stores. Several of the aircraft suppliers that I have listed in my mail.txt carry both styles. Fresh air masks are better, but require a greater investment. Skin exposure is much worse than air exposure and the effects are more pronounced.
Symptoms range from swollen eyes and running nose to skin cracking and draining.
Be very sure that you work with latex or vinyl gloves and change your gloves frequently. Urethane and Epoxy resins are absorbed into the gloves and after a while you may as well not be wearing any. Watch out for poor quality gloves. A lot of cheap gloves contain pinholes or they are very porous. Gloves like these can be very dangerous.