You will need medications only if you have any symptoms of hypothyroidism, otherwise just repeat your thyroid test after 3- 6 months. Symptoms of hypothyroidism for your reference are as follows- Anxiety, feeling low , hair loss, fatigue, cold sensitivity, constipation, dry skin , puffy face , hoarseness, Muscle weakness and unexplained weight gain. And for cholesterol make few changes to your diet( eat healthy / nutritious food, avoid fast/ fatty food) and physical activity ( atleast 40 min of brisk walk per day) and repeat the test after 3 months.

Sub clinical hypothyroidism should be bade cause for all , it should be addressed

You have to start taking medications for hypothyroidism

At 1st, try diet and exercise method If failed, need medications then