How to i remove off a counter once with an event and not every time it reaches a specific number?
Are you trying to say when the counter reaches a number, you want it to delete?
I think you need to use an additional condition, for example:
Player/Counter/Not Equal To/10 AND Player/Sensing/Collided With Object/Enemy DO Player/Counter/Add/1
Or you can use the counter value correction with a global variable, for example:
Player/Counter/Equal To/Global Variable AND Player/Sensing/Collided With Object/Enemy DO Player/Counter/Add/1