Blisters

Question
I have an angel fish that has developed blisters on it's uper lip.  I change the water ever 8 days or so and using 3 caps of Melfix once a day for the past 10 day. I have a 30gal tank and my test strips show all is within the correct range.

Answer
Matt,
could be a parasite under the skin, or a fungal infection.
hard to tell without looking at it.
the melfix is a very slow working cure as it is not very strong.
As long as the water parameters are ok continue as you are and watch.
if things develop further , mail me back.