Welcome to Microsoft Community and thanks for posting the question.
Based on the description it looks like you are unable to use Touch Pen on Windows 8 RT, it would be great
if you could answer these questions in order to assist you further.
Are you getting any error message or error code?
Have you made any changes to the computer prior to this issue?
I would suggest you to refer the steps from the following Microsoft article and check if it helps.
Touch and pen settings: Frequently asked questions:
If you need any other information about Windows, feel free to post your questions and we will be glad to
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