my boy had bad skin condition when he was 2-4 months old too. yes, change his mittens often so that the saliva does not aggravate the condition. clean his face often gently with cooled boiled water and cotton pad. dont't ever rub or try to burst it as it will spread the germs and worsen the situatuion!!!
finally be patient. pimples probably dont't bother the baby as much as it does the parents - newborns dont't know 'vanity', lol!! finally, my pediatrician, Ong EK, was right on the spot when he said the skin condition will clear up after 4 months usually, becos exactly that happened for my boy - it was almost like overnight! so just be patient and dont't ever blame yourself ya.
my pediatrician also said erratic skin condition among newborns is common because their skin and sebum production are still in the process of stabilising after them being in mummy's womb for so long and having gone thru the birthing process where sometimes mummy's hormones can also upset their sebum production.