2 yr. old with a cold?

My 2 year old son has a cold. His nose gets very stuffy and filled up and he hasn't learned to blow his nose yet. (we're still working on that) So I am having to use one of those sucky things to help him out. But every time I get everything out he ends up with a bloody nose. Any idea why? I am very gentle when doing it and I am extremely careful not to go to far up in his nose but it still happens. Should I be worried? It doesn't bleed to the point where it is running out of his nose, just enough to make the edge of his nose red with dried blood.