Praise be to Allah.
Does leakage of blood and water from wounds break Wudu?
With regard to blood that comes out from anywhere other than the front and back passage , there is a difference of opinion among the jurists as to whether it invalidates Wudu or not. The most correct view is that it does not invalidate Wudu ; this is the view of Imam Malik and Imam Ash-Shafi`i (may Allah have mercy on them both) and it is the view favoured by Shaykh Al-Islam Ibn Taymiyah (may Allah have mercy on him).
Can you pray with blood on your clothes?
With regard to what gets onto your garment of blood or pus , if it is a small amount, there is nothing wrong with you praying in that garment. If it is a large amount, then you have to wash it or change your garment, according to the majority of jurists.
Some scholars are of the view that blood that comes out of a person’s body from anywhere other than the front and back passages is pure and not impure.
Shaykh Ibn `Uthaymin (may Allah have mercy on him) said: “The view of those who say that human blood is pure is a very strong view, because the texts and analogy indicate that." (Ash-Sharh Al-Mumti` 1/443)
And Allah knows best.