How Can Thumb Dots Which Bleed Are To Be Treated?

hi and thanks in advance! i have little black dots just under the skin on my thumb if i rember right i cut this thumb right where its at with a box cutter yrs ago dots come and go if i prick the skin ever so much it bleeds good for a while( first time i ever seen it thought it was a thorn and trid to pick it out ) what to do?