Honey Boo Boo Crash -- Pumpkin Rushed Back to Hospital

Honey Boo Boo's sister Pumpkin has been rushed back to the ER after complications from a serious car accident last month ... TMZ has learned.

13-year-old Pumpkin was taken to a Georgia hospital last night -- and sources tell us, it's because she's still experiencing serious pain in the wake of the January 6th car accident that injured several members of her family.

We're told Pumpkin has been complaining of bad headaches, neck pain, and nausea -- all signs of head trauma. A rep for TLC tells us, she was admitted to the hospital for a battery of tests.

As we reported, Honey Boo Boo, Mama June, Pumpkin and Jessica were all passengers in the car, which was driven by Sugar Bear. Police later determined Sugar Bear was at fault.