I did a little research on this and turns out heat is the main proponent required to ripen green tomatoes, not sunlight. This blogger mentioned sunlight inviting rot and toughening the skin. The rotting on my tomatoes was more of a sunburn at the very top, which I always slice off anyway. Further, the texture of the skin seems normal. However, next time, I am encouraged to try his brown paper bag and banana method.
How do you force-ripen tomatoes?