Regarding your finger’s condition, rather than apply topical medication, you need to deal with the cause. I’m guessing you don’t know the cause though it can only be one of two things. One thing is that it is caused by exposure to chemicals or some other external stimulation. The fact that it is only your little finger though makes that less likely unless you’ve been sticking it in places which expose it to conditions that the rest of your hand isn’t being exposed to. If you start watching yourself and noting what you do, you can discover if it is an external situation causing this. Also, pay attention to how you wash your hands to see if you’re not washing that finger as well as the rest of your hand, or not drying it or something. Pay special attention to how you handle your hands after using the bathroom or dealing with cleaning products. The likelier candidate is stress. I used to get itchy tiny little bubbles on my fingers from stress and fatigue. They’d pop up between my knuckles and the first joint on my finger. In that case, you know what you need to do. Steroids are not a good long-term solution. They’re really quite bad for you, as you discovered. I don’t trust Japanese doctors solutions to small problems. They solve the tiniest little loose screw with a sledgehammer or essentially a placebo.