as Jawge suggested,, a sinew patch would be my call,, when I have a knot on the edge like that I am nervous and try to lay my bow out so it is not on the edge,, but if that is the only way,, I would put rawhide or sinew on it before I started to tiller( and leave that part a bit stiffer),, ,, rawhide might hold as well, but I think the sinew is a bit stronger,,,