How can I fix my mowhawk ?

Even it out make it slimmer and use a styling product to shape it how you want it to look. Otherwise the whole mohawk thing isn't gonna work

Get a hand mirror, so that when you cut it in front of your bathroom's mirror you can look at the back of your head. Good lighting helps too. 

Go get it fixed by a professional 

Maybe it needs to be narrower, and more symmetrical.

Ever heard the expression, "you can't fix stupid"?

have a professional fix it...............

start over, shave it all off.......

What's with the Mohawk ?  You still a rebel ?

Your hair should be a similar length all around. It looks like there's a noticeable difference in length at the crown of your head.

Cut the whole thing off.