How To Treat The Dry Semi Hardened Skin On My Chest?

i have dry semi hardened skin on my chest between my pecs and goes down almost to my belly button. the affected skin is a little darker than the surrounding skin (i'm light skinned). It doesn't itch, it flakes and a little scaly. i'm male 5'5'' 160lbs and have had this for around 2 years. it was thought to be tinea versicolor but treatment only helped very short term