is my Betta sick?

Question
I bought a new betta fish today, to replace the one that was recently killed by my 6 year old brother :( Anyway, I noticed that he has a strange bump on the side of his head, above his right eye. He's acting fine, swimming around normally and everything, but should I be worried about this bump?
I have a picture, its at http://i63.photobucket.com/albums/h138/staki1/bump.jpg

I don't know how many gallons are in his tank, its a smallish fish bowl. The waters at room temperature, and he's the only fish in the bowl. At the moment he is still in the small plastic container from the fish store, I am waiting for the water in his bowl to come to room temperature. As you can see in the picture, the water from the pet store is somewhat dirty. The container is about the size of a small cup I guess.

Answer
I, in all honestly, have absolutely no idea what the exact cause of this strange bump is. I believe it could be a harmless tumor (with the information that has been given). I suggest keeping a very close eye on him for the next few days.  Feed him a well balanced diet, keep his water clean, and make sure the water remains between 72-74 degrees. If anything goes wrong or his behavior seems to change, message me back with the symptoms and I can do some more research on it from there.

Also, I'm going to suggest buying a 5 gallon tank for your Betta fish. Just as humans, Betta Fish can suffer from muscle deterioration in small places and grow stressed which can lead to a poor immune system to common diseases such as Fin Rot or Dropsy(despite the myth of a Betta Jar or Bowl). Your Betta should be fine in the small bowl for a few months (if you need to save up some money). At PetSmart, I know you can buy a 5 gallon tank (head to the small reptile section) for between 15-20 bucks and a small filter can be bought for about 10-15 bucks.

But to the actual question - I have done some research in some of my books and online and it seems to be a harmless tumor. Please message me if anything seems to change.

Thanks for you question and please forward any further inquiries to my account.