Camera shutter not opening

The best thing you could do is take it to a competent repair shop, tell them what happened, and have them fix it. If it is just sand jamming the lens cover, they shouldn't charge too much to fix it.

Alternatively, if you can move the lens covers at all, try gently working them back and forth in very small movements while holding the camera with the lens pointing down - basically just try to work the sand out and let gravity help you. Be careful though, you may get sand deeper into the camera's mechanisms this way!