There are three options, two of which are bad, one of which is regrowth (Which if you see on the body is not so likely).
Excess slime coat is one possibility, and is the least frightening option. The others are columnarious or fungus. Both thrive at warmer temps, and can be fatal in a very short time frame. For both treat with AQ salt. I would suggest you QT her, as they can be extremely contagious. 1 tsp/gal is a safe dosage to start her treatment with. Depending on which disease you may need to raise it to 3 tsp/gal. A picture would really help.
IF you could fill out the form here http://www.bettafish.com/showthread.php?t=49233
we will have a better background as to what is going on.