My Granddaughter Came Home Saturday Night..she Swears She Has Not

My granddaughter came home Saturday night..she swears she has not used for 6 days does not want to live that wait. Took her to Dr Sunday as her throat was "killing" her. She had smoked meth! She is 18. She didn't tell Dr she smoked meth. He gave her loratadine 10mg one a day and azithromycin 2tabs day one 1 tab days 2 through 5. Plus salt water gargle. She is still not feeling well. What can she do? Thank you