If the brown scars are like lines on your tomatoes, then my guess would be that they have split. This occurs when the soil dries out and is then watered which causes the tomato to split. The scar is the split sealing up. The scar will never disappear, and I would suggest harvesting your green ones, as I will be doing shortly, as I very well doubt that we will be getting some nice hot and sunny weather.

After harvesting your tomatoes, put them in a paper bag. You could also introduce a ripe banana, as they release ethene gas which encorages ripening. Bananas are good at making things ripen.