I have an older American made Oscar Schmidt 15 chord autoharp. I bought it used and when it arrived the sound board (top) was bowed in towards the back. If you look across the top over the sound hole it is obvious. There is no sign of gapping around the perimeter of the harp, and no sigh of the top coming unglued from the sides. It is just bowed in towards the \back. The harp still sounds good.
Is this something that needs to be repaired or can it be used as is without a repair bill?
Thanks

Dave