Im tatted all over the place from neck down, and the only place I ever had the white dots is my inner left bicep.
The only thing different about that tattoo ( besides being the best 1 i have ) is that the artist used dry aftercare.
Instead of A&D, aquaphor or a brand name aftercare, my tattoo was wrapped up dry beneath saran wrap and suffocated for 48 hours. This is the cleanest heal of any tattoo on my body.
About 6-8 weeks later i had the white bumps exactly as described above. I think they went away after about 2-3 weeks.
Funny part is that its a tattoo of a fish and the white bumps looked like "ick", a parasite that appears as white bumps on fish =)