Wife received a refund from dentist she paid in 2022, but received the refund in 2023

My wife had dental work in 2022 that she prepaid for, we were not married at the time.  Mid April 2023 she received a $3800+ refund because the dental service ended up not costing as much as she was originally quoted.  When I am adding up our medical expenses, I believe I would add this as a negative amount, thereby reducing our total medical expenses, in our medical expenses.  Is this correct?