Yes. You need to retake. A 790 is only about the 74th percentile. That’s horrible!! Additionally, it means you had to have gotten about 6 answers incorrect. That’s unacceptable for T20. Indeed, an 800 is not much better as it’s only about 79th percentile.
Fortunately, the College Board has recently added a new score for Math 2 - 800*, which indicates that the applicant had a perfect score with all questions answered correctly. This is the new gold standard, and is really the only acceptable score if applying to T20.
And if you believe all that, I have a bridge to sell you. 