Praise be to Allah, and may Allah’s peace and blessings be upon the Messenger of Allah, his family and his companions.
As to what follows:
In response to your question, we say, and with Allah Almighty lies all success:
I ask Allah Almighty to cure you. As for changing your clothes, then you are not required to change them in order to pray. That is because blood and pus are pure according to the correct opinion amongst the People of Knowledge. For, in Sahih al-Bukhari, it has been reported that the companions used to pray with their [open] wounds. So if blood was impure, they would not have been allowed to pray like that. Hasan al-Basri said, as Bukhari related from him, “The Muslims have not ceased praying in their wounds.” So it has been mentioned here, as we mentioned earlier, that it is not necessary to change clothes that have been affected by blood or pus, so long as the blood is not menstrual or post-partum blood.
Your brother,
Dr. Khalid al-Muslih
29 / 9 / 1424 AH