ingrown toenail
Medical and everyday term for a toenail that curves and grows into the skin, causing pain and inflammation.
My ingrown toenail is so bad that it hurts every time I walk.
For treating ingrown toenails, proper nail trimming is important.
Compound of 巻き (maki, 'rolling' or 'curling') and 爪 (tsume, 'nail'), with rendaku voicing of つめ to づめ. The word describes a nail that curls into the flesh.