The best course of action is to have the blister swaped and sent for a culture or PCR test for herpes. Also you should consider getting tested with a type specific igg test to see if you are positive for HSV.
Has your boyfriend been tested to know his own status?
http://www.ashastd.org/herpes/herpes_learn_oralherpes.cfm is a terrific site for more reading about oral herpes.
these sound exactly like cold sores. You and your partner should consider getting tested for herpes so that you know who has what and can decide if you have any need to take any precautions or not together or oral and genital sex.
Thank you so much everyone. well, I just recently told my boyfriend and told him to get tested. the redness is still present but there aren't any blisters. i'm confused... thanks again
don't hesitate to see your provider for a proper work up on yourself too.