Help with damaged screws in canon 18-200mm lens.

[LPPhotography]

I have a canon 18-200mm EFS that, out of the blue, stopped zooming.
A brief background story: 3 months ago, it suddenly wouldn't zoom back to it's widest angle. When I tip the lens around, I could hear that something was loosen, I thought it was a piece of glass loose. Then last week, without doing anything different, the zooming was so stiff I couldn't manage to zoom at all. However, I was out on a session, and had to use a little force to turn it to 50mm focal length.
Just the other day, I took it apart. I managed to take off the end cap where it goes into the camera, the metal case, the circuit board, as well as the connectors. After that I came upon some screws on the outer black rim that were extremely difficult to take out, and they were also very easily chipped, being as careful as possible to slowly turn, but it still chipped.
I tried all that I could think of: putting a rubber band over the screws, slicing the screws with an xacto knife to make new grips but to no avail, tried using the star screw drivers. None of them did anything. One option that I have left is to use a dremel tool to help slice the screw top so I can turn.
My concern is that, though it will definitely make a slit on the screw top, it will also damage the body, and I don't want that to happen. For those who have taken apart lenses before, do you have any suggestions for me? or do I have no choice but to use the dremel?
With this lenses out of service, I have also been out of service. Any suggestions is welcomed. Thanks.

And please don't tell me to take it to the shop. If I have the cash, I would have taken it without a thought.

 

[bratkinson]

Without trying to be snide, what could have been a $100 repair, or, perhaps, even fixed under warranty, may either become quite expensive to repair or end up require replacing the lens.

 

[gsgary]

This is a good reason to get rid of that junk and get a good lens