HI Greg,
Those bumps are related to water quality...Think of them as pimples or zits. They are generally harmless but can get infected if too big. They will rupture and leave a small hole that should close up with no problems at that size. Basically they are an indicator that your water may not be good enough.. Bacteria gets into the fishes pores and these pimples are the result.
is too little, especially in higher pH's I would suggest increasing the frequeny of water changes and be sure the filters are clean..weekly 40% water change
hth,
al