skimmer help

[Fphipps]

ive had my skimmer on my tank for about 3 months and its been working great. i recently treated my tank with melafix for an issue i was having with a fish. the instructions said to turn off sterilizers and skimmers, which i did. well treatment is over and i plug my skimmer, open it all the way up to break it in again and its just spewing bubbles out of the top. the only reason i can think this is happening is because of the melafix that may still be in the water. i have the plug on the bottom of the collection cup out and its still open. will it settle down? do i need to do another water change? im fairly new to skimmers so any input would awesome!
thanks!