Boyfriend had a prostate biopsy lst wk, we had intercourse last night and his semen was mixed with blood and he came inside me should i panic?

No, don't panic: I'm not sure what it is you fear - but you would not 'catch' his prostate disease. Un protected sex would expose you to pregnancy risk and STDs even if there were no blood - use protection for those reasons. I hope he can deal w/ his condition, but panic is not going to help anything. Best!

Blood: Bloody semen can occur for a number of reasons. The medical term is hematospermia and is more common than many realize. Contact the surgeon who performed the biopsy and discuss further. Here is a good resource of information: http://emedicine.medscape.com/article/457632-overview