Had What Seemed To Be Friction Blood Blister Or Spider

had what seemed to be friction blood blister or spider bite on upper outer bicep of arm. small raised like pimple but bright red. it got scraped off. lots of blood. applied pressure around 10 minutes and arm held upright. finally stopped bleeding. covered with sterile gauze pads & wrapped w/medical tape, then wrapped gauze bandaging around. it was healing nicely; would change dressing and be on lookout for infection. none. over course of 2-3 weeks flat, looked good; went down to antiobiotic cream and bandaid. it started to grow back. burst again today when taking bandaid off to clean and redress, before derm appt. tomorrow. breast cancer 16 rears ago. very anxious. takes long time for bleeding to stop to apply bandaging. now feel i should wait for it to reheal a bit again before doctor. concerned jumping into shower too soon will start bleeding again. what could this possibly be and thoughts on allowing to heal a little from new burst today. thank you; have typed one-handed. still keeping it raised.