I hate bumps. They are intrusive and annoying.
To answer your question.. something is wrong with your chameleon's eye. If you haven't seen the many, many, MANY posts on eye problems with chameleons, you may want to do a search for them. A long shower or really long misting session once a day to start, in addition to your regular misting schedule.. if that doesn't fix it within a couple days, a vet visit may be in order for a round of antibiotics. In the meantime, you need to look at your husbandry. Is your humidity too low/high? Temps? Vit A? Cleanliness? The only good thing I can think of about chameleon illness is that it immediately forces you to look at what you are doing wrong and correct it.
Heika