What happens when you have an ingrown toenail for too long? does it get badly infected?

Treat Ingrown Nails: An ingrown nail will eventually cut into the skin and create a portal of entry for bacteria. Symptoms would include swelling, redness, drainage and pain. It is important to have the offending portion of nail removed asap, in order to prevent further spread of infection. This is an easy in-office procedure performed under a local anesthetic. Most podiatrists also use a cold spray prior to injection.

Yes it can: And it will get worse until you get it fixed.