Yes, Sales and Use Tax does factor into the equation regarding your Business income. Depending on how your business is structured and the manner in which your books are kept Sales and Use Tax is entered in different ways:

1. If you paid Sales Tax to your vendors on purchases the Sales and Use Tax Portion of the purchase is already factored into the final price of the purchase and of course you may consider this an expense. 
2. If you paid Sales and Use Tax for an item that you resold, the Sales Tax that you paid will be considered a Cost-of-Goods-Sold and consolidated with the final price paid for the item. 
3. If you paid Sales Tax which you collected from your customers it can either be deducted (adjusted) from your business' income or considered an expense out of a liability account.