Hi there can anyone please help me identify this problem and what I can do to resolve it? My guinea pig Wombat does not seem to be in pain or bothered by it at all but I don’t want her becoming unwell if it’s left unaddressed. I don’t know how old she is, possibly 2-4 years old, I rescued her because her buddy died and the family wanted to rehome her. She is so good-natured and happy.