Hi I'm waiting on an appointment with dermatologist as I have a very discoloured thumb nail -had for 2 years but now more discoloured-/ my GP had never seen anything like it 

fungal infection ruled out by nail clipping test 

but treated for 9 months with Terbinafine "just in case"

nail bed aches at times

very painful if I bump it 

are there other infections this could be ??? I've googled everything and still no further 

it is from the top of my nail bed and covers 75% of my thumb... cuticle area is clear... very mixed colour of yellow black and green 

I totally understand no one can diagnose me on here but just looking for some advice... freaking out it's melanoma