Thanks everyone for their replies..

Candy- sorry i should have clarified, i didn't have the heating thing on for 2 hours later, what i meant was the redness/bruising was there to hours after already haven taken it off.

Its interesting you mentioned something about diatbetes... i'm actually going to get tested for that, and i'm kind of leaning towards thinking i might have it, especially because this weekend I fainted at work for no reason.....