Why isn't my running script working/changing the values?

It's a LocalScript in StarterPlayerScripts. Children are speed, maxSpeed, maxExp, exp, level, running. All are NumberValues except for running which is a BoolValue. It's supposed to start off at WalkSpeed 16 and give you exp while holding R over time. The values aren't changing and the output says Pressed r Running Released r Running when I do just that.

local player = game.Players.LocalPlayer

local mouse = player:GetMouse()

local speed = script.speed

local maxSpeed = script.maxSpeed

local maxExp = script.maxExp

local exp = script.exp

local running = script.running

local level = script.level
	
	
	mouse.KeyDown:connect(function(key)
		if key == 'r' then
			print("Pressed "..key)
			player.Character.Humanoid.WalkSpeed = speed -- Start Running
			running.Value = true	
			print("Running")
		end
	end)
	
	
	mouse.KeyUp:connect(function(key)
		if key == 'r' then
			print("Released "..key)
			player.Character.Humanoid.WalkSpeed = 16 -- Stop running
			running.Value = false
			print("Walking")
		elseif key == 'e' and speed.Value ~= maxSpeed.Value then
			speed.Value = speed.Value + 16 -- Increase speed
			print("Speed increased to "..speed.Value)
		elseif key == 'q' and speed > 16 then
			speed.Value = speed.Value - 16 -- Decrease speed
			print("Speed reduced to "..speed)
		end
	end)
	
	
	while running do
		wait(3)
			exp.Value = exp.Value + 15
			print("Exp is now"..exp.Value)
	end
		while true do
			wait()
			if exp.Value == maxExp.Value then
				level.Value = level.Value + 1
				print("Level is now"..level.Value)
				exp.Value = 0
				print("Exp is now"..exp.Value)
				maxExp.Value = maxExp.Value + 105
				print("maxExp is now"..maxExp.Value)
				maxSpeed.Value = maxSpeed.Value + 16
				print("maxSpeed is now"..maxSpeed.Value)
			end
		end