Zaid Alsalami, Shaykh Dr Zaid Alsalami is an Iraqi born scholar, raised in Australia. He obtained a BA from Al-Mustafa University, Qom, and an MA from the Islamic College in London. He also obtained a PhD from... Answered 4 months ago

Bismihi ta'ala

It is haram to intentionally swallow blood, and so if you know you have blood in your mouth, you should spit it out. If you are in the state of prayer, and you taste blood, or for some reason you know you have blood in your mouth, you can spit it into a tissue and continue with your prayer, or wait until you finish your prayer, and then spit it out. 

And Allah knows best.