I don’t know about that lump, but it looks like your chameleon has mbd. We can help you with your husbandry, but you need a good vet who has experience with chameleons. Attaching the vet list. Can you post more pics of your chameleon and its enclosure?
Sorry your going through this, I’m a new carpet owner and have no idea, so going to follow for the advice as well. Welcome to the forum! Everyone is great here.