How To Get Rid Of Dent In Toenail?

There is a horizontal dent in my big toenail, and it s been there since last year when I played tennis, I think my sneakers may have put pressure on it or something. Although the dent is still there, I d like to prevent it from getting any worse but also to continue playing tennis this year. What can I do to prevent it from denting any more? (More of my nails were dented last year but grew out)