It won’t let me add in my business expenses

Are you sure you have a Form 1099-SA?  That form reports the distributions from a Health Savings Account (HSA).  Did you receive self-employment income reported on a Form 1099-NEC?

Business expenses are reported on Schedule C - Profit or Loss from Business.    Entering a Form 1099-NEC will trigger the program to prompt for business expenses.  A 1099-SA will not.  

To report self-employment business expenses, make sure you are working in your return,

• From Tax Home, 
• Select "Income & Expenses"
• "Self-employment income and expenses", click on Add/Edit
• If you haven't already, set up your business, or
• Click on Edit, and then select the Expense Categories you want to add to