What if I do not know the amount of my medical expenses, but I know they were much higher than $1636?

If you didn't keep track of your medical expenses then you cannot claim a deduction for them. You have to have records to support your deductions.

But note that, on your federal tax return, only medical expenses in excess of 7.5% of your Adjusted Gross Income (AGI) are deductible. (Enter the full amount that you paid in TurboTax. TurboTax will subtract 7.5% of your AGI.) In addition, medical expenses are an itemized deduction. They will not reduce your tax or increase your refund unless your total itemized deductions are more than your standard deduction.

You cannot claim medical expenses in TurboTax Free Edition. You would have to upgrade to Deluxe or higher.