Have you provided him with receipts showing the medical expenses in a timely manner? As in, within a month of the expense being incurred? If not, you may or may not be able to get reimbursed since it is not spelled out in your order in regards to timelines.
My DH never bothered sending receipts to his ex since she wasn't even paying her CS, much less anything else. He didn't feel the need since he knew she wouldn't pay. Down the road when the state finally put her in jail over the child support, he asked about those expenses and was told that they wouldn't be usable since he didn't provide copies of receipts in a timely manner to her.