There should be a medical item you can apply to yourself that brings you a sudden jolt of 'energy', regaining SHP (perhaps at the cost of HHP?). Application should take time so that it can't be used in combat (maybe like a 1 minute timer).
I'd spread this suggestion into something larger, like an alchemy system that can actually make sure of the various herbs, fruits and bodily pieces we have already- but i'm sure there's a plan for that already eventually.