My 3ds XL has taken some damage at the hinge and I can still open it but I'm afraid that if I play with it too much then the damage will get worse and I won't be able to play on it anymore. I'm not sure what to do. Do you guys have any ideas?
Something similar happened to my regular DS when the part of the hinge connecting the two halves together began to crack. It was around the time when I got my 3DS, so it wasn't much of an issue with me. Best thing I'd say is to see if the Geek Squad from Best Buy can repair it. If you're in the US and close to a fairly big city, there should be one nearby. You'll have to pay some money for the fix though.
You would have to ring them up and ask. Or better, bring it into their services/repair department and they can do an analysis for you. Best Buy repair services can be expensive, but it depends on what needs to be fixed. Can't really think of an estimate, so expect to pay anything from as low as $20 to a high of $100 or so.
I think you can also send it to some company affiliated with Nintendo to get it fixed, but if it's the original 3DS, they've stopped doing repairs for those. I'm not actually sure if that costs anything or how much it costs either.
Is it just the hinge? If so then they would have to replace the outer casing of the device. Depending on if it's the top, bottom, or both; it could cost about $50 or so depending on the cost of parts and labor. It would be cheaper to do it yourself, but I would advise against it due to the warranty and the fact that it is easy to kill a 3ds that way. There are many places that can repair these. If you live near a mall, some computer and laptop repair shops also repair nintendo devices.