I was taught that this can easily happen if the walls were not properly primed before the paper went on. What you can do is get some sizing paper (just plain paper that is very similar to the texture of wall board when it's put up) and apply it like wallpaper. Just make sure you coat it with the proper primer before you paint or paper to make sure you get the final look you want.

If you're papering it's probably fine to leave like that, though for paint you may want to cover it with joint compound and texture it how you like.

One of the easiest ways to make this work is to buy yourself a box of drywall mud and put it up on the walls. If you pretend you are icing a cake with it you can create whatever surface you want from smooth, which I wouldn't recommend because of effort and time needed to make it perfect, to dramatic. You can make it have "some" depth so that all of the boo-boos will just go away. Once you have it up on the walls you go over it until you get the surface that you want but don;t get too concerned about pointy areas because once it is dry you can knock that down with some fine sand paper. Don't get too carried away with the sanding part because it makes a lot of dust. After it is dry, paint your base coat and then your top coat. Good luck!