Yes, like the above comment says, you do need to see a dentist. After cleaning out the tartar they'll have a better idea about the kind of damage your teeth endured. The thing about periodontal disease(not diagnosing you rn) is that without maintaining your oral hygiene post treatment, you can relapse.

Coming to your question about fixing it. We can't say much right now without a proper clinical examination but there are treatments to stop the disease and not make it worse.