Is it normal that i taste blood when i'm nervous or scared

Sure, there's this: "Oral mucosa heals faster than skin, suggesting that saliva may have properties that aid wound healing. Saliva contains cell-derived tissue factor, and many compounds that are antibacterial or promote healing. ... Saliva also contains an analgesic, opiorphin."

But there's also this: "Human saliva contains a wide variety of bacteria that are usually harmless in the mouth but can cause significant infection if introduced deep within an open wound. ... The thumb had to be amputated after the wound became infected with flesh-eating bacteria."