Humpback is serious, can model training be corrected?
It can be corrected. I'll introduce you to a more effective method: you can correct humpback with a mattress to correct it frequently. It's called spine mattress, also called head mattress. Usually it lasts for three hours at a time. When finished, you can put a customized pillow on it and use it as an ordinary mattress. It is the best method I know at present, and it is easy to stick to.