Yesterday I was skiing and I overshot the landing of a huge booter and my shin hurt to walk and have a very sharp pain if something touches it. There is no visible bruise so I'm not sure what happened.

If you can't tell if your shin is broken, we sure can't tell either. If you think it may be broken, it's time to have someone look at it.

I have to say though, I am fairly experienced with broken bones... most of the time, you will have bruising and swelling. This is no guarantee though so you are probably better off getting checked out to be safe.