All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
If the wound is not already covered with a dressing or bandage, it is not incumbent to wrap it in order to wipe over it during Ghusl or ablution; rather, the person should wash it that is possible provided that there is no fear of harm on him nor of delaying the healing process. If he cannot wash the wound, then the scholars held two different views as to whether he should wipe over it or perform Tayammum.
The Hanbali scholar Al-Mardaawi wrote in his revision and commentary on Al-Furoo‘ (by Ibn Muflih):
"If the body part is wounded and there is no fear of harm by wiping over it, scholars held different views as to whether he must wipe over the wound or perform Tayammum ... One view is that it is sufficient to wipe over the wound without performing Tayammum and that wiping over the wound is obligatory in this case. This is the correct view that was stated by Shaykh Taqi Ad-Deen, as he said, 'If he is wounded and it is feared that the wound would worsen if it is washed, it is better to wipe over the wound than to wipe over the bandage, and this is better than Tayammum...'
The second view is that it is obligatory to perform Tayammum over the wound ... This is the chosen opinion of Al-Khiraqi... He also said, 'The obligation is wiping and Tayammum...'"
Ibn Qudaamah wrote, "If the wound is not covered with a dressing or bandage, we have previously underlined that the person should wash the healthy parts and perform Tayammum for the wound. Hanbal reported that Ahmad said regarding the wounded '...if he fears harm, he wipes over the wound and washes the area around it,' i.e. he wipes over the wound if it is not covered with a dressing or bandage." [Al-Mughni]
We believe that this matter is flexible by the Will of Allah, and there is no problem if the person wipes over the wound instead of performing Tayammum or performs Tayammum instead of wiping over the wound; the prayer is valid in both cases and the person does not have to repeat it. If he performed Tayammum, he does not have to follow the correct sequence in ablution; he may perform Tayammum over the wound before or after the ablution. Shaykh Ibn ‘Uthaymeen, may Allah have mercy on him, said, "This is the correct view in this regard, and it is the chosen view of Al-Muwaffaq, Al-Majd (Abul-Barakaat Ibn Taymiyyah), and Shaykhul-Islaam Ibn Taymiyyah, who declared it preponderant in his book Tas-heeh Al-Furoo‘."
Allah knows best.