Hi.

since you injure your patient when you roll a critical miss when trying to heal. does the patient get knocked back by one space, making it impossible to heal the patient until the pieces are moved back into adjacency?

thx

No, critical misses never deal knockback.

No knockback as it is not an attack.

Just damage from the failed support roll.

As it's been said, Support is not an attack, so the critical miss damage will not cause any knockback. If you try to heal a mystic and accidently damage him instead, you won't take feedback damage either