I have a blood blister that I discovered at 16. It was small (about the head of a pin) when I first found it. I popped it, thinking it would drain and heal. Over the years, with each popping, it has grown to about the size of a pea. It's been here (on my middle inner thigh) for 7 years now. It's not painful, but if it's rubbed, it pops and it bleeds a lot, for 30 minutes at least.i have varicose veins, so I know my veins are not circulating well.