Ingrown Toenails, Baby Toenail Growing Backwards, Fungi On Big Toes. Treatment?

hi , im 14 f, 5ft5 8 stone . i have ingrown toenails. my baby toenail grows backwards. since i can remember. all the rest other than my big toe grow forward and turn down. my baby toe on my right foot used to grow backwards , now it is just growing side ways. im just wondering can i treat this problem at home myself, and what are the reasons for my baby toenail growing backwards? also my nails on my big toes are yellow/brown. im sure this is caused by fungi as it grows in warm moist places. is there a way to treat that? i don t wear sandels etc. part of the problem im sure. thanks.