I Have A Skin Tag On My Breast Next To

I have a skin tag on my breast next to my nipple. It has been there since my sons birth. Two days ago, it appeared to have a blister on it. In the shower the blister popped and appeared to go away. It came back (the blister) and may have popped again but now it is flat and blood colored. I need to know if I should go to the doctor or not worry about it.
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