My baby has this dark marks/ scars from insect bites. How can I lighten them?

You can try these home remedies as suggested by this article: http://smarts-tips.blogspot.com/2013/07/how-to-remove-scars-mosquito-bites-on.html#.Vrq3DRhTMQ0 - Use lemon juice, rub on mosquito bites. Allow 10-15 minutes then rinse with warm water. Repeat 2-3 times a day. Avoid wearing too long because of the high content of vitamin C in the lemon water can irritate baby's skin. - Use lavender oil. Apply at the blackened skin for 15-20 minutes then rinse with water. Repeat 2-3 times a day. - Wear a banana or watermelon skin. Brush in mosquito bites. Let stand for a while and then rinse with cold water. Take advantage of aloe vera gel. Apply it on the skin for several hours. - Grate the yam pieces. Rub the bite marks of mosquito. Let stand until dry and then rinse. - Brewed green tea with warm water 5-10 minutes until dissolved, and then wipes the blackhead mosquito bites.