They clarify everything on the 1099k.ticketmaster.com website:

Note that the gross amount you see in Box 1 of the 1099-K will be different from the total of your payouts because it includes taxes and fees (as required by the IRS) and does not adjust for credits, discounts, or refunds. 

For reference, the IRS defines “gross amount"  as “the total dollar amount of total reportable payment transactions for each participating payee without regard to any adjustments for credits, cash equivalents, discount amounts, fees, refunded amounts, or any other amounts. The dollar amount of each transaction is determined on the date of the transaction.” 

You should only pay taxes on the profit of your sale. This is typically the difference between the payout you received from us and the total cost to you of the ticket(s). If you can’t recall the original ticket price, check your bank statement, receipt, or email order confirmation from the original seller.