Heated perches are a gimmick - birds don't need them EVER no matter how cold it is because nature gave them a special blood circulation 'mechanism' that makes it so they never get frostbite even when they are standing on ice (it's called 'counter-current heat exchange circulation'). Please remove this perch from the cage and don't use it again.
If the bird has been standing on dowels all along, the most likely 'direct' (I will explain the 'indirect' below) cause is the perches so you need to change them for tree branches instead. Use branches in three main diameters, one a bit too big, one perfect (this is a perch of a diameter that allows the bird's toes to wrap around it with the tips of its front claws not touching the tips of the back claws) and one a bit too small. And don't make them all perfectly parallel to the bottom of the cage, either. For now, wrap them in something soft (I use paper towel) and give the bird a platform-like place so he can put his feet flat on it. I would make sure its feet are clean to avoid infection but I would not put anything on them (not even vit E oil) unless there is an open wound (sore).
Make sure the bird has plenty of fresh food to eat because, aside from the bad perches, lack of betacarotene in the diet causes it, too (this is the 'indirect' cause). Dark leafy greens and orange and yellow veggies do the trick (try baked sweet potato, butternut squash, cantaloupe, etc) but, if the bird has been on a bad diet for long (mostly seeds and not enough produce), you can get a multivitamin/mineral supplement and use it daily for a week or so (don't overdose, make sure you are giving him the right amount because, when it comes to vitamins/minerals and birds, more is NOT better).