I am a carrot. I've been to see doctors, therapist, the lot and there is nothing that can be done. They've told me i can't get surgery to become the carrot i am inside so i imagine it would be similar for your situation.
I've grown up in Essex amongst the orangest humans on earth and doctors think this is where my situation came from. Do your family or friends look like potatoes? perhaps the men in your family are bald?
Anyway I do what i can to express my inner carrot. I wear fake tan and have dyed my hair green. i've had breast implants and made my legs as skinny as i can. I believe now that i am closer to becoming the carrot shape i dream of. I imagine this must be harder for you, but how about shaving your head? putting on weight and become more round? And if you want something more permanent than body paint perhaps a tattoo in 'potato colours' would be ideal.