Clicking noise isn't bad thing. It means they are happy.
Does his bump look anything like that? ^^
If it is like that then it's nothing to worry about. It may just be an impacted gland, like a pimple. It should go away after a while.
If it doesn't start to go down within a week or has some kind of discharge then it is something to worry about.
It's still best to have a vet check it to make sure.