is there a way to add exp to an already written script?

This is where I want to add the Exp when killed.

local Humanoid = script.Parent.Humanoid
function PwntX_X() 
local tag = Humanoid:findFirstChild("creator") 
if tag ~= nil then 
if tag.Value ~= nil then 
local Leaderstats = tag.Value:findFirstChild("leaderstats") 
if Leaderstats ~= nil then 
Leaderstats.Zims.Value = Leaderstats.Zims.Value + 250 
Leaderstats.Kills.Value = Leaderstats.Kills.Value + 1 
				
						
 
wait(0.1) 
script:remove() 
end 
end 
end 
end 

this is my Exp script

game.Players.PlayerAdded:Connect(function(player)
	local level = Instance.new("IntValue", player)
	level.Name = "Level"
	level.Value = 1
	
	local exp = Instance.new("IntValue", level)
	exp.Name = "Current"
	exp.Value = 0
	
	local maxExp = Instance.new("IntValue", level)
	maxExp.Name = "Max"
	maxExp.Value = 100
	
	
	exp.Changed:Connect(function(val)
		if exp.Value >= maxExp.Value then
			
			
			level.Value = level.Value + 1
			exp.Value = 0
			maxExp.Value = maxExp.Value * 1.25
		end
	end)
end)

workspace:WaitForChild("GiveEXP").ClickDetector.MouseClick:Connect(function(player)
	player.Level.Current.Value = player.Level.Current.Value + 25 -- Use this whenever you want to give the player exp.
end)