So I made a script that when touched it damages the player
but I noticed if the exploiter deleted it on the client side the touch event won't fire is there any way to check?
Well as far as I know, you can't exactly "delete" the workspace, but I do think I understand what you're asking about.
To actually detect when something has been deleted, you can use Instance.ChildRemoved
or Instance.DescendantRemoving
.
However, I don't believe this is what you're asking.
I'm guessing you've written some local code that should actually be handled by the server. If that's the case, be sure to use a server script to handle that kind of code.
That could be anything from the server interacting with other users, special conditions that the client shouldn't have control over, etc.
If you need some help grasping the client/server model for roblox, there's actually a decent article on it by Roblox here: https://developer.roblox.com/en-us/articles/Roblox-Client-Server-Model
In your specific case, since the script is damaging players, you should use some code on the server, not on the client.