I wrote on myself with a pen and it's weapping up and itching what does this mean?

Allergy probably: You are probably having an allergic reaction to one of the chemicals in the pen. Wash the area well. You could apply some over-the-counter cortisone cream if you have some. If it doesn't get better in a couple of days, you may want to have a doctor look at it. Pens are for paper as you've probably figured out - don't do that again, please.