Wudu while wounded
Question

What should a person do if one of the areas normally washed during wudu is wounded?
Praise be to Allah.If a person is wounded in one of the areas of wudu and is not able to cover the wound with a bandage, he should perform wudu except for the wounded body part, for which he should then perform ablution with sand (tayammum).
(Note that this means one performs normal tayammum, not actually placing the sand on the wound itself.)
Al-Mughni ma'a al-Sharh il-Kabeer 1/282.