Good resolution.
I thought it would have been hard to give the curse back as the bastrd didn't cast it, he was a "victim" of it and passed it someone else, in its original state it was just a annoyance for him, but the shaman he found ignored the consequences or the right way to deal with it, so he made him turn in it into a deadly curse.
Of course, the bastard doesn't deserve salvation, ruined some of the best years of a poor woman and pushed to suicide for the heartbreak + likely damaged her trust in others, and his last sin was passing the curse to a child of his own will, to a child, a literal monster, in a serie with actual monsters drifting around.
I feared he would be let of it scot-free as not being the curse caster it wouldn't bounce back magnified and in other stories I've read when acurse is passed to someone else the original victim was freed from it, nice that the snake used a simple solution, recalibrate its target, and the boost to its power was logical.
Nice that the unfortunate woman survived.