Terrified about this tooth

[gemcool16]

I needed a small filling in my upper right molar. Unfortunately my old dentist quit and then I had a bad experience with a private dentist. I managed to get a referral to special care dentistry but it's taken a year. Recently some enamel came off, it isnt painful at all but its brown under the enamel. It feels very hard not soft and doesn't hurt when I poke at it.

Could this tooth be saveable or it is a goner?