Have you tried aloe vera gel? it's helped mine a lot (even a bit on those over 3 years old), works better because it's think and gloopy. £5 for a tube from health food chain shop.
Other than that, i hear you can get waterproof coverup stuff through a Red Cross Clinic (ask your GP for a referral apparently)
Someone has written about their experience with it here (WARNING images of scars to show effectiveness of product):
http://purple-noise.blogspot.com/201...amouflage.html
Hope that helps xx