Pimple on traumatic tattoo removal site

My 9 yr old son had a traumatic tattoo surgically removed from his face (just to the right and below his mouth, near his chin) a couple of months ago.  The surgeon said put paper stiches in and told me that they would dissolve over time.  However, even though the surface stitches have actually gone and the incision site is pretty much healed a small yellow-headed pimple keeps appearing on the spot where the stitches were.  Also, there seems to be a small hard lump under the surface of the skin.  He says it's not sore but I'm wondering could these pimples and lump be from some sort of infection or could it simply be that he just keeps touching it with grubby 9-yr-old boy fingers?  I put tea tree oil on it and aloe vera which seems to clear the spot and then after a week or so it comes back.  Any suggestions?

[Howard Rosenberg, MD]

A common problem is a dissolvable suture that is coming to the surface.  These sutures produce an inflammatory reaction, that sometimes extrude through the skin surface.  Your surgeon would be in a position to evaluate the likelihood that this is occurring.  Another cause would be cysts that occasionally form in a sutured wound as a result of ingrown epithelial cells from the skin surface.  In either case, these problems often resolve on their own without treatment, but if they persist, should be seen and treated by your surgeon.