What are my rights as Salary (Exempt) in TN regarding hours and PTO being takend

I work for an employer that has labeled me salary (exempt) since I was hired, due to the nature of my work (IT). Most days I end up staying later than 95% of the office and I almost always work more than 40 hours/week. My question is related to when my employers are actually allowed to take PTO/money out of my paycheck for leaving early a day or two to meet doctor appointments and such. For example, last week, I worked a total of 45 hours but was gone one morning for about an hour for a doctor's appointment, and as a result another hour of PTO was removed from my pool. The paycheck prior, I was retracted 5 hours worth of pay for a similar situation. Is this legal? This seems like a contradiction of what I have been explained regarding the rights of salary exempt employees. Thank you for your time and assistance.