It's always best to keep your cool when working with computers. But sometimes that's difficult with the problems they cause. One serious problem is repetitive strain injury, caused by weeks, months and years of making the same small movements over and over again.

In my case, it's not the keyboard that's the problem - it's the mouse. Using the mouse, and particularly the scroll wheel, causes a burning sensation in the back of my hand. I try to use my left hand when I can, and I avoid using the scroll wheel altogether. But I have to use my computer and the pain persists.

One way of finding relief is to cool the affected area. I have got into the habit of using a bag of frozen peas from the freezer. This seems to work quite well, although obviously it is no cure.

However the other day I thought I would try something better - a freezing mixture such as you would use to make ice cream!

This consists of ice cubes, salt and water. As the salt dissolves in the water it causes a physical process that cools the mixture even lower than freezer temperature. I put the mixture in a plastic supermarket bag and applied it to the affected area.

Blessed relief!

But after a few seconds when I removed the bag I noticed white spots where the ice cubes had made contact. One patch of skin had actually frozen and was hard to the touch.

And now this is the result - a case of frostbite. Thank goodness it's not serious and should heal quickly. But I've never heard of anyone getting frostbite as a result of using a computer before.