Bad vs. Badly

This from an AP story on Social Security disability:

Patricia L. Foster said she was working as a nurse in a hospital in Columbia, S.C., in 2005 when she was attacked by a patient who was suffering from a mental illness. Foster, 64, said she injured her neck so bad she had a plate inserted. She said she also suffers from post-traumatic stress disorder.

Make that she injured it so badly. "Bad," the adjective, is perfectly fine if you say you are feeling bad. But you injure yourself badly.

The migration from adverb to adjective seems to be led by phrases such as "eat healthy." Let's see if we can slow it down a tad.