Any cure for receded nail bed + yellowish-dull dark nails? Please Help!

hi,

when i was really young, my dad cut my nails with a nail clipper too close to my nail bed and clipped it too short. ever since, my nail bed has been curved and has never grown back. also, my my big toenails have a black stripe near the corner, but i think thats more of a genetic thing. I used to have alot of rough lines on my nails but they're smooth now, now that i file the surface and use NonyX gel. They also can get very yellowish sometimess.

so my questions are:

how can i repair my nail bed?
is there a way/formula that can brighten my nails?
do you any suggestions to make my nails look better?

thank you in advance!!!