mc7

Oh, I can say something about how the foreskin usually functions without a frenulum. The foreskin will still move to cover the penis (the taper causes most of that). But it won't be as tightly attached obviously. You must have had a tight frenulum before?

What it won't do without the frenulum is move out of the way of the penis automatically like it did with a functional frenulum. Without the frenulum, the foreskin can sometimes get in front of the glans in such a way that it gets bruised by the motion of the penis (which probably must necessarily be rapid). This looks like a bruised lip. (The foreskin is extremely vascularized like a lip.) I think you can avoid this pretty easily just by being aware that it can happen and consciously avoiding it. (And it doesn't hurt at the time that it's bruised, you might just notice it's a little swollen and tender afterward.)

There are only capillaries in the frenulum itself, but there are small veins beside the frenulum. Maybe the vein is swollen from some injury its received? I think the vein should probably stay inside the skin surrounding it, even if it detaches too. But I don't know. Obviously if it should begin bleeding uncontrollably, you'll have to have a doctor mend it. But I would guess you should be fine.

If it looked more hazardous than I'm acting like it is, you might be able to ask your doc about it on the phone (cheaply & easily).