HELP! i think my hamster has a swollen testacle?

ok i have a 3 month old teddy bear hamster and tonight i checked him and it was like swollen there? just one big ball thing then i put him back in his cage and got him again, now it looks like it..idk deflated? like theres little wrinkley skin like a balloon looks when the air gets out? what could it be? help please?!