... so she grabbed a towel and dried off. (Para. 5)
Meaning: she quickly took hold of a towel and dried her body with it.
dry off: (cause to) become dry
The swimmer dried off in the hot sun. 游泳者在烈日下晒干身子。
She ran in after the rainstorm and dried herself off with a thick towel. 大雨过后她跑进来，用一块厚毛巾把身子擦干。