If a dermatotogist injects a max of 5mg/cc of a corticosteroid for facial cystic acne, how many ml is he actually injecting?

1 ml: If he's injecting just 5 mg, and it's 5 mg/cc, a cc and an ml are the same amount, so he's injecting 1 ml.

Depends: 5 mg/cc is the concentration of medication in the solution being injected. It doesn't really say how much (how many milliliters or ml) of the solution actually goes into the skin. It depends on the number of lesions injection and how much goes into each individual lesion.