If you received a 1099 for the work you performed then it was not a "favor". You were paid for the work and it is reportable income. As you were provided a 1099 MISC this payment to you will be reported to the IRS by the person who issued that 1099 to you. First check to make sure the amount on the 1099 is correct (matches what was paid to you). If it is not request that the issuers corrects and files an amended 1099. If it is correct then you will enter and report this income as other income, usually on Schedule C. You will transfer the information from the 1099 into Turbo Tax.
Also your "friend" likely issued and filed a 1099 to you so that he/she could deduct that amount as a business expense on his/her tax filings.
To skip reporting this one-time income as 'Self-Employment Income', when entering your 1099-Misc, choose 'this work is not like my main job' and that you 'had no intent to earn money' (screenshots).
This will put the income as Other Income in your return, instead of Self-Employment Income.