Hurt you or the metal?

The directions on the can should include instructions on its use which typically say to wash off exess with water which seems counterproductive as it can cause flash rusting. If you wipe it down quickly though it really is not a problem. I have used it on small areas and then wipe up the excess with a damp rag. Prior to any primer being used in that area I typically profile the metal with 80 grit on a DA and then degrease the area.