If she continues to do it, try putting Jane on a leash attached to your waist so you can correct her and praise her when she doesn't do it. Just like I had to do with Loca, only it was to stop her from trying to eat my cat. It worked!
Try to relax, ok? There's nothing you can do until you speak to the vet. Like Mary said, Harley's recovery won't be linear and he's probably still not feeling great. Keep us posted, OK?
It might be good to continue with the group training. Maybe the trainer can show you what to do if Ben goes after another dog, and maybe being in that environment would help acclimate him to small dogs. Group training could be good! Phoenix passed with flying colours and he even learned how to sit! Neither Loca nor Treasure learned a thing but they had fun and it was good for them to get out and be around other dogs.
Please have him checked for tick disease. Phoenix had babesia when I adopted him and it wasn't expensive to treat. Left untreated, TBDs can cause death.