Hi, I don't have a drawing tablet, and can I use my mouse?
You can use your mouse, but it's not ideal. It's like using a rock for hammering a nail. While it can be done, a hammer is a better tool for the job.
The mouse lacks pressure sensitivity and the natural hand-position of drawing. A mouse is fine for testing sculpt mode but If you find yourself sculpting a lot, you'll want to invest in a tablet.