Antibiotic weight gain

My daughter was to do 3 months on doxy for acne.. Over two months she had stomach aches and really had to take the med on a full stomach. The antibiotic noticeably increased her appetite. She was hungry all the time. She looks bloated and her belly looks bloated. She had none of these issues and hunger before. She has always ate regular meals at regular schedules and fairly conscientious of good choices. But her intake definitely increased. She has gained 5 pounds. That isn't much, but she is an active 13 year old who dances 15 hours a week with other activities. It almost seemed overnight. Now that the gut flora is damaged, can it be restored and how? It would be nice if the doctors were more open about the side effects as I sure don't want her to have a lifetime of altered metabolism and digestive issues. Should there be tests done to help restore her gut health.

Thank you, I am taking her to see her doctor as well as the dermatologist to see how to move forward successfully.