Photoshop eraser tool help

[nightangel73]

Okay I'm learning photoshop and I'm try to use the eraser tool. I have seeing several tutorial videos and do exactly as they do however it's not working for me and I don't know why..

I choose the eraser tool, adjust the settings, then try to erase but it just doesn't show in the picture what I'm erasing, It doesn't mark what I'm erasing. However in the layers pallette it does shows what I'm erasing.. Can somebody tell me what I'm doing wrong? Thanks

 

[ocular]

Duplicate the layer and then click the eye under the 2nd layer.