Gritting his teeth until it feels his muscles will burst, Jon tries to stamp out the approaching swarm to prevent re-infestation while healing himself and readying the blunderbuss to ignite the hopefully soon to be incoming lanterns. He would call for them, but he is in no condition to speak intelligibly without belying his image.

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swift to lay hands (1d6)[6] on self

reflex (1d20+9)[28]

ready action to blast the swarm/laterns when thrown

attack swarm (1d20+5)[23]
damage (1d8)[2]

attack lantern (if needed)(1d20+5)[25]
damage (1d8)[3]