After Harper is shot below the shoulder, she is crawling on the ground, barely able to move. After she defends herself against the attacker (using her arm on the side where she was shot), she gets up and uses both her arms normally for the rest of the movie, showing no signs of being in pain.
When the characters phones were being checked before destroyed, the first phone dropped said Monday November 20th, the other phones said November 1st.. which was the correct date being after the midnight of Halloween.
Harper limps inconsistently after having her foot impaled.