How can I fix my chewed up LEGO head? When I was about 8 I used to bite down on loose LEGO heads to "fix" them. Of course after the heads "treatment" they would have chew marks around the neck.

Is there any way to make these marks less noticeable? One of my old favorite LEGO heads have these marks. I can't buy a replacement because the head isn't made anymore. 

I could buy one on ebay... If I had my own credit card/paypal/etc. and my mom would gain the knowledge that ebay isn't evil just because it's online. What should I do? 

The only idea I have is to put some nail varnish over the chew marks. 



Here's a picture of the head. I don't know if it helps much since you can't really see the chew marks.
Your best bet would still be BrickLink. Many sellers there accept cash, checks or money orders, so you don't necessarily need paypal or a credit card. However if you would like to work on fixing the bite-marks on the head you pictured above, there are several things you can do: 


If the bite-marks are not too deep, you can sand down the area with very fine sand-paper to make it more even. The sand-paper must be very fine, otherwise the surface would end up getting even, but rough. I have found wet and dry sand-papers the best as it can provide a very smooth finish.
You could try your nail-varnish idea, but please note that nail-varnish actually melts the plastic, so use only very little. You might also try other type of clear varnish that is fairly thick. Make sure you try it first on a piece you don't care for to see how it reacts with the plastic.
Because plastic is fairly soft, I found that sometimes you can smooth out bite-marks just by the back of a kitchen knife. :)