wa'alaikum as'salam wr wb
If there is a wound in any part of the body, then this wound is either uncovered or it is covered with a dressing or bandage.
If it is covered with a dressing or bandage, then he should wash the healthy parts of the body, then he should wet his hand with water and wipe over the dressing. If he does this then he does not need to do tayammum.
But if the wound is uncovered, then it must be washed with water if possible, but if washing it will harm it, and he can wipe it then he should wipe it. If that is not possible, then the wound should be left without washing or wiping, then when the person has finished doing wudoo’, he should do tayammum.
https://islamqa.info/en/69796