Thankyou for your help!! Yes I will definitely have a look online at vets near me who have a lot of experience with chameleons. I will get them to have a look at it and see what they say.
Unfortunately there is a chance he may be wild caught as I did get him from a pet store (he was still a young juvenile). He got the lump on his head when he was about 1 years old, so this made me think it didn't have anything to do with the lump as he is now 4, but I can understand if they are...
Your Chameleon - I have a male, Veiled Chameleon he is roughly 4 years old and has been in my care for 4 years as well.
Handling - I handle him about 3-4 times a week but does vary a lot depending on the mood he is in.
Feeding - He gets a mixture of crickets and locusts, but mainly locusts...