Small Skin Growth

Question
My female American Staffordshire Terrier Always has 'blackheads' on her nipples no matter how often I bathe her or how frequent she swims in the local river.  One of these blackheads at some point became a pimple and popped.  It healed fine with no infection but where it healed it grew back as tissue the same color and density as her nipple.  Its been a couple years now and I've noticed that this growth is definitely larger, however it must be growing at a really slow rate. It almost has the appearance now of another nipple.  Is this something that I should worry about? Is there anything I can do to prevent 'blackheads' and pimples, they only seem to be on her nipples.

Answer
The only way to prevent blackheads is to clean these areas with alcohol frequently.  Alcohol will help dissolve the oils and prevent them from drying out.  She may get more blackheads (comedones) if her thyroid levels are low.  If this has grown to the size of another nipple, you might want to have your vet look at it to make sure it isn't a tumor growth.