The black area under the chin looks just like normal pigmentation tbh. I don't see any scale loss - they're there, you probably just can't see them individually because they're so dark. The spot on the tail, however, does look abnormal - maybe a mechanical injury that got infected? Or very early stages of fin rot? I honestly don't know what it could be. Keep an eye on it & make sure the water parametres are perfect. Maybe add some catappa leaves (or extract), it helps relieve stress & has antibacterial properties. Hopefully it will heal on its own, but if it doesn't, do let us know.