Abu Bakr (may Allah have mercy on him) said: I heard Ata bin Abi Rabah, Mujahid bin Jabr and Tawus (may Allah have mercy on them) saying about a man whose finger had been wounded: He should wash off the blood that has got on it, then bandage it, then wipe over the bandage when he performs ablution; and if the blood seeps through until it appears, he should replace it with another bandage, then wipe over it when he performs ablution.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1085