How do I get the screen to shake when the player holds mousebutton1?

Here's the script I made to make the screen shake on click, however it only works when I tap click. I want it to work when the player holds lmb:

local character = script.Parent
local plr = game.Players[character.Name]
local mouse = plr:GetMouse()
local mousedown = false
local cam = game.Workspace.CurrentCamera
local shaking = false
local radius = 0
local Decounce=true
mouse.Button1Down:Connect(function()
    if character:FindFirstChild("Humanoid") ~= nil then
        radius = 20
        radius = 150
        if (shaking) then return end
        shaking = true
        repeat
            wait()
            if radius ~= 0 then
                character.Humanoid.CameraOffset = Vector3.new(math.random(-radius,radius)/100,math.random(-radius,radius)/100,math.random(-radius,radius)/100)
                cam.CFrame= cam.CFrame * CFrame.Angles(math.random(-radius,radius)/14000,math.random(-radius,radius)/14000,math.random(-radius,radius)/14000)               
                radius = radius - 13
            end
        until radius <= 0
        shaking = false
        character.Humanoid.CameraOffset = Vector3.new(1,1,0)
        mouse.Button1Up:Connect(function()
        mousedown = false
        end)
        mouse.Button1Down:Connect(function()
            mousedown = true
            repeat
                wait(0.01)
            until not mousedown
            end)

    end
end)

Please help me fix my script!

Button1Down is an event, meaning it executes its code once until the event is triggered again. You will want to make a loop that goes until Button1Up is triggered.

Something like this

mouse.Button1Down:Connect(function()
	until mouse.Button1Up do
		-- your code
	end
end)

this might not work though. If it doesn't, try something like

mouse.Button1Down:Connect(function()
	until variable do
		-- your code
	end
	variable = true
end)

mouse.Button1Up:Connect(function()
	variable = false
end)

UserInputService is a good way to tackle this problem. You are able to connect a function to both when the input is started and ended.

Try something like this:

local US = game:GetService("UserInputService")
local Player = game.Players.LocalPlayer
local playerMouse = Player:GetMouse()

local isHoldingButton = false
local INPUT_TYPE = Enum.UserInputType.MouseButton1

spawn(function()
	while wait() do
		if isHoldingButton then
			-- Rest of code.
		end
	end	
end)

local function checkInput(Input)
	local UserInputType = Input.UserInputType
	if UserInputType == INPUT_TYPE then
		-- Let's check if they are currently holding it.
		if not isHoldingButton then
			-- They are not holding it, so lets say they are.
			isHoldingButton = true
			return
		end
		-- They are no longer holding it.
		isHoldingButton = false
	end
end

US.InputBegan:Connect(checkInput)
US.InputEnded:Connect(checkInput)