I can tell you what long term Antibiotic use has done to myself (6 years).
#1 it made my Acne worse and it spread on my body
#2 it really messed up my digestion. I suspect it killed off most of my beneficial bacteria and replaced them with bad bacteria like fungi (yeast)
#3 it has caused me to develop Arthritis like pain in my joints
#4 it gave me testicular infections (so bad I couldn't walk) that would happen for a few days every 2-3 months
#5 It gave me abdominal cramps that were very intense and lasted 4+ hours
#6 My mouth became infected with sores and my gums became sensitive to anything hot/cold, although the sores have gone away...to this day I still can't brush my teeth without experiencing extreme discomfort.
I am sure there is more, but those are the ones I know for sure were caused by Antibiotics