Self-employed health insurance deduction goes on Schedule 1 line 17 (which goes to 1040 line 10), as long as the expense is not greater than your net self-employment income. If it does exceed your net self-employment income it gets split automatically. An amount equal to your net self-employment income goes on Schedule 1 and the remainder gets added in to medical expenses on Schedule A.
It will not show up on Schedule C and not reduce any SE Tax on a net profit. It just reduces your AGI if you itemize on Schedule A.
Where did you enter the Medicare premium? Medicare plan B payments are qualified as Self-employed medical insurance premiums and should be entered under Business instead of in the SSA-1099 Social Security Benefits section.
Go back and delete it from the SSA-1099 entry screen. Try going to the search box by My Account and type in Social Security Benefits. That will give you a Jump To link to take you directly to it.
