If your skin comes into direct contact with an unknown material, the first thing you should do is

Remove that material and wash well with water first and then water and soap ..
Check for any allergic reaction and consult a physician if suspecting any sort of allergy present or there is a history of such incidents ..
Meanwhile, you may also consider taking an Anti-Histamine medication of the most-safe over the counter group like Loratadine or Desloratadine as to the recommended doses ..
If an allergic reaction is started and there is a risk of the fatal Anaphylactic Shock your physician is very likey to administer Adrenaline IM (intramuscular) to you immediately .. Again this is as to your physician and am just mentioning it here for the sake of sharing information :)

Best Luck!

Wise