Stoma bulge

Hi, I'm 50 and was diagnosed with rectal cancer in March. I my operation which left me with a permanent colostomy I'm May. I've been coping and managing fine but have put about 10 pound on after my chemo and I've noticed one or twice this last week that my stoma has protruded! This shocked me but after holding a dry wipe to it, it shrunk back in. I was wondering if this is normal?