I used to get ingrown toenail on my right big toe all the time. They were so bad, I had to have them surgically fixed every time. The Dr. thought she was gonna fix it once and for all the last time by injecting silver nitrate into my nail bed. She said the down side was that I wouldn't have a toenail on that toe ever again but the up side was no more ingrowns.
My toe nail grew back despite the silver nitrate stuff AND I haven't had an ingrown since. I'm a winner.