How can you tell if you have a partial chicken pox rash (had the vaccine long ago)?

Mild case. Small percentage of individuals who had received chicken pox vaccine experiences mild form of disease with much fewer bumps. Currently, 2 doses of chicken pox vaccine are recommended, typically at 12 months and at 4 years of age.
Or... ...There may be a large number of bumps, but very very small ones (i saw this a few times when the vaccine was just getting started). The bumps were so small, i never saw any scarring from them.