birthmark changing

ive had this birthmark since birth, a coulpe of freckles surrounded by one freckle that looks smeared. but starting about 1 year ago it began to bleed ALOTE it scabed over and from there it got bigger and has changed the other day i noticed it swelling a bit and it almost looks like a blister has formed. any insight to this will be much appreciated
p.s. i was suppose to have it removed mostly cause it was annoying me but missed appt.It hasnt been biopsied