I have this black pimple. Its not acne. There's one in my right leg. Another in my right arm, It has something to do with blood
The description suggests that the pimple is probably ingrown hair. This condition happens when hair grows into the skin. This should go away on its own. However, you should have the acne checked by a dermatologist for medical advice.
It sounds like a blackhead.
I would have that checked by a dermatologist. Yes, I have had so called blood pimples, too. But always have something black checked out.