Yes! Don't be so lazy, you must go to the doctor to get it checked to avoid any future problem. Prevention is always better than cure
I've Had A Black Scab On My Leg For Over Six Months; Should I Get It Checked Out?
You said "scab" that normally would make one think that it is the result of some type of bite or injury. It sounds more like a tumor or a mole. What in the shower aggravated the spot to make it bleed? How was the spot after your shower. Was the scab smaller, less puffy? Would you have known it was bleeding had you not seen the blood? Did you have a minor bump on a chair or table? I would really be concerned and not investigate it. Unfortunately you may have a blood clot forming under the scar, and we all know that can be deadly. Have it checked out, perhaps call your physician and he will advise you. Hope it is a minor problem.
Personally its nothing.... Don't listen to what everyone else has said. Its nothing really and you don't need to worry about it.