Ideally, a doctor or nurse should clean wounds that are large, deep, or dirty, and abrasions caused by gravel. There is a risk of infection, and also a risk of permanent tattooing of the skin from gravel, dirt, grit, etc., which remain in a wound. Wounds longer than 5 cm or which involve deeper tissues than the skin may need stitches. If part of the wound has dead or damaged skin then this may need to be trimmed or removed to prevent infection developing in it. If you suspect the cut has damaged deeper tissues such as nerves, tendons, or joints. Wounds caused by penetrating glass, metal, etc., may need to be carefully examined, and may need an X-ray to check that there is nothing left inside. Gaping wounds should be closed with stitches, glue, or sticky tape. All wounds of the face should be seen by a doctor immediately in order to keep scarring to a minimum.