Talk to Dermatologist on Foot Nail Issue

i am 21 years old....about 2 years ago i wore sneakers that were tight..and they hurted all day long due to my foot nails being long.....both the thumbs of my feet became dark in colour...and with each day became darker and darker....then as they grew long crack appear horizontally....and when that crack reached the top...it broke....both my nails became okay....then from one year one of that nail became yellow and has spots on it...see the picture below...what is the treatment?