Oh wow well FIRST i would cut just a mohawk to see if u can still pull it off and if you can i'd leave it and proceed w colour and then if NOT i would i think make it like....more the same length idk we could do longer or shorter just not this weird mushroom length. i'm thinkin a little longer not much.
and like i think i could do a lot w platinum or even and don't get scared like actual white for contrast some of yr terrible dye job and roots could be there but itd look like more hot DRAMATIC and less hot MESS.