Another slip up is you'll get frustrated by always trying to reach him--and you'll take damage from the pills, which is all he's looking for. He can't kill you with pills. Take it slowly and focus on not getting hit by the pills, you can DED to cancel their hitboxes, then he'll eventually learn his pills are accomplishing nothing (if you never mess up anyway.) Your goal is to slowly close the distance between him and yourself, not allowing him to reset the distance by getting around you. That's how you change the game from him pressuring you with pills to you pressuring him with spacing.
You don't need to be within range of hitting someone to pressure them, only enough to cramp their space.
EDIT: It is frustrating. But you'll need to switch your mindset to deal with situations like this, ("ok, gameplan change, *deepbreath* let's be slow and methodical) and secretly you can revel in the fact that he does feel pressured too.