You say these expenese are related you your ex. If you were married, you could have deducted these on your joint return. If you filed separately, it is a little less clear. If you guys did deduct these on a joint return, and you are just looking for some type compensation from him, that will be very tough if it wasn't covered under the divorce decree.
Medical expenses, subject to the various limitations imposed, are deductible in the year incurred.
Assuming you filed your individual income tax for 2008 in 2009 then your right to amend your 2008 return may have expired on April 17th. If you have a tax return, check the date it was filed and count three(3) years from that date.
If you take the deduction, but get reimbursed by your ex, voluntarily or by court order, then you received a tax benefit and must report the reimbursement as additional income, or as an offset of your current year expenses.
You probably need to assistance of a good CPA rather than an a tax attorney, but in either case, you should definitely seek assistance, and, more importantly if this is a part of your Property Settlement Agreement or Final Judgment of Divorce, you should consult your family law attorney to file a Motion to Enforce Litigant's Rights. I suspect you are responsible for the first $250 of medical expenses as part of the child support paid, but only a reading of either of both documents will make this clear.
If you need the name of a good family law attorney, I know of one in Westfield and two in Livingston. I can be reached at 973-994-9080.
The foregoing is not intended to be legal advice upon which you may rely as I have not been retained for this purpose.