If they're eggs then just give him a bath and they should just go away. I would still get medicine just in case. I don't think there are any rat safe lice stuff in stores though, can only really get them from vets. I could be wrong but I know it's like that for mites. Also clean the room they live in very well. Especially the carpet to prevent it happening again.
That could well be lice eggs. i would go to the vet to treat him as he's young and dosage can be tricky. Also treat all his cage mates. revolution or ivermetcin are worth doing. One treatment should shift it
My vet told me using Dawn soap(the one with the picture of a duck on it) is something that helps with the lice. She told me to wash the rat and cage with the soap. She also told me to throw out all his toys, hammock, and wooded house (due to the lice being on the objects.) So i just bought him new things.
Theres a picture of the soap I bought for my rat Good luck