Question about my pubic hair?

Ok so i did a poor job of shaving and now there are red bumps and super stubborn hairs on my pubic region. What caused this even though I did use shaving cream? How can I prevent this from happening again? If I just leave it alone, will the red bumps and super stubborn hairs eventually go away? I hope I don't have to buy anything to solve it cuz my mom would kill me. Lastly, how long will it take for my pubic hair to grow back? I just plan to let it grow all the way out.