Do medical expenses include what part the insurance didn't pay for? like half the bill?

Health care insurance premiums, including dental and vision insurance premiums, and other medical expenses that you paid with out of pocket funds and were not reimbursed are an eligible medical expense that you can deduct using Schedule A for itemized deductions. However, only your total medical expenses that are greater than 7.5% of your Adjusted Gross Income (AGI) can be deducted. Your total itemized deductions reported on Form 1040 Schedule A must be greater than the standard deduction for your filing status to have any tax benefit.

Standard deductions for 2023

Single - $13,850 add $1,850 if age 65 or older
Married Filing Separately - $13,850 add $1,500 if age 65 or older
Married Filing Jointly - $27,700 add $1,500 for each spouse age 65 or older
Head of Household - $20,800 add $1,850 if age 65 or older

Yes if you paid them and didn't get reimbursed.  You can only deduct the amount of unreimbursed Medical Expenses you actually paid over 7.5% of your AGI.  And then all your itemized deductions have to be more than the standard deduction to get any benefit (so you would only be getting the benefit of the amount that puts you over the standard deduction).  And since the Standard Deduction is increased more people will not need to Itemize.

For 2023 the standard deduction amounts are:

Single 13,850 + 1,850 or 65 and over or blind

HOH 20,800 + 1,850 for 65 and over or blind

Joint 27,700+ 1,500 for each 65 and over or blind

Married filing Separate 13,850 + 1,500 for 65 and over or blind