[John honestly isn't sure what to do here. Frisk can't carry Lutha, which is what John would do. Lutha won't accept medication and Frisk can't exactly force it on the man.]

Frisk, I know this is gonna be awful, but you might need to wait this out. This kind of pain can't last. Or at least it can't last at the level it is forever. It'll come in waves. You need to wait for him to come down from where he is, and then get yourselves as far as you can before the next wave hits. Do you think you can do that?