Almost everyone has a same experience that wearing glasses for a longer period of time, there will be dark mark on the nose. Especially when the eyeglasses do not properly fit your nose or are too heavy. The mark will be darker. So there are some ways for you to get ride of/avoid the dark mark.
1. Remove your eyeglasses now and then and do a message on your nose.
2. go to your optician for a help on finding a pair of glasses with a comfortable bridge and well-fitting nose pads
3. Use makeup to get rid of dark marks from your glasses.
4. Switch to contact lenses to avoid getting indentation marks from glasses.