Photoshop bracket keys/circle question

In my attempts to learn PS, Im erasing the foreground in a picture so my BG shows through. When I use the bracket keys to change the circle size, the size is changing, but I cant see the circle. I only have cross hairs. So until I actually click on the eraser, I dont know how big its going to be. Hope this makes sense. It just changed on me so I know I must have clicked something. I was using it just fine then all the sudden my circle went away and I'm left with cross hairs. Its showing me the size and I can adjust it, I just cant see the actuall size. Can any one enlighten me on what I did and how to change it back so I can see the size of the circle?

Press the Caps Lock key. It toggles the cross-hair and circle. I think that's what you're looking for.

For what it's worth, I would avoid the eraser tool. When you use it, you erase data that you can't get back. It's called destructive editing. Your best bet is to learn how to use layer masks. It's a little tough to grasp at first, but it's well worth your time to learn. You can go back and mask/unmask anything at any time - even years later.

Thanks MG. it worked. And yes, Masking is a good idea.

Also, if you press shift+[or shift+] you change the hardness of the brush in 25% increments.