The first question is: How old is the tattoo? Is it *completely* healed?
If the tattoo is not completely healed yet you should not touch the scab and you certainly should not have a razor near it. Be aware that a tattoo *can* be slightly raised for weeks (in rear cases even months) after it was done, and you can’t use a razor on it, BUT if your tattoo is older than 2 months and it is still raised, you have a problem. In this case the person who did the tattoo probably went in the skin too deep (in the 3rd layer of skin, aka: Hypodermis) and you might have some permanent damage to your skin. This condition can not be diagnosed via email or with a picture, so your best bet is to see a professional tattooist face to face and have him/her look at it, or consult your GP right away.