Is it possible i damaged the cpu by raising the volts too high, pc wouldnt boot and the mobo blinks red now
Yes, it is. Of course it is. That's exactly why you shouldn't overclock unless you educate yourself CORRECTLY so that you know exactly what you are doing.
What is your CPU model, motherboard model, and what did you raise both the core voltage and the frequency TO?
Cod will lag on 4k resolution now