1) Is there any problem in using products which have collagen or they boost collagen in your skin?
2) And what if you're not sure what the source of collagen is?
3) My cream says Collagen Boosting Cream. That should be ok to use, right?

1) If the origin of the collagen is from non eatable animal or an animal not slaughtered according to sharea’a, then it is not allowed to be consumed
2) If it is possible that it it is taken from vegan origin, then it is ok.
3) If it is for external use, there is no problem, as you can wash it.