I borrowed from my ira but repaid within 60 days. where do I show the repayment

First, IRA loans are illegal. You actually took a distribution and rolled it back within 60 days.  After you enter the 1099-R in Federal > Wages and Income > Retirement, there will be questions.  Some of them ask about rollovers/repayments.  Also note that the account owner can only rollover IRA funds once every 12 months.

Please follow these steps to enter your 1099-R and the return of the funds within 60 days:

1. Login to your TurboTax Account 
2. Click on "Search" on the top right and type “1099-R”
3. Click on “Jump to 1099-R” and enter your 1099-R
4. Continue "Tell us if you moved the money through a rollover or conversion" and select "I rolled over some or all of it to an IRA or other retirement account within the time limits (normally 60 days)"
5. Continue answering the questions.