You have very short hair what will happen if you bleach it?

It will go white and your head might sting and itch. Just as if you had longer hair. It does not matter wether you have long or short hair, the outcome will be the same. Just as above it doesn't matter what the length of your hair is. The only thing that matters is the condition of it. If your hair is dry then it will cause your hair to ger dryer.