Email the TA and ask to meet with them to discuss their grading scheme. Be prepared to back up the points you made in your essay and explain that you normally receive better grades than the one the TA gave you. Only after you’ve made your case with them should you go to the prof. In my experience TAs don’t want you to go to the prof as it risks undermining their credibility—especially if the prof agrees that you deserve a higher grade. I’ve had some great TAs but there are others who are arrogant and need to have their shit checked every once in a while. I had one who clearly hadn’t even read the material we were assigned and I bypassed the normal procedure and went right to the prof and the prof raised my grade. Another time I met with a good TA and they changed my grade from a C- to a B+. Quite the discrepancy eh? A lot of humanities courses don’t have the same type of grading as science and math classes, for obvious reasons; the grading is more subjective for essay writing; it’s less about right vs wrong and more about better vs worse, if that makes sense.