It is narrated from Abdullah bin Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) "granted a concession for praying in a garment stained with the blood of boils." And Ata' used to pray with it on his garment.
Only Baqiyyah bin al-Walid narrated this from Ibn Jurayj. Abu Ahmad Ibn Adi al-Hafiz said: This hadith is known only through Baqiyyah from Ibn Jurayj, and it is likely that between Baqiyyah and Ibn Jurayj there are some unknown or some weak narrators, because Baqiyyah often does that.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4096