Generally, sales tax collected is not included in gross income.

Since it a trust fund tax and is being collected on behalf of the state, it is not part of anyone's income (except the state).

However, if you did receive a 1099 that includes the sales tax that was collected, you will need to include this amount in your income.  You will then take a deduction equal to the amount of sales tax remitted.  The sales tax amount can be included with taxes, or you can add a separate line item under "Other miscellaneous expenses".