Function calling itsself?

I seem to have spaghettied something up here. This function is supposed to check for an IntValue, who's value is incremented by picking up an item in the world. However, even if you pick up said item, the animation and the healing won't work, They only work when I add a script under the IntValue setting it to any positive number. I can see in the explorer that the Value increments correctly when I pick the item up. But it seems to ignore that and rely entirely on the Script that sets the value manually. Why is this happening?

local humanoid = script.Parent:FindFirstChild("Humanoid")
local stims = humanoid.Stims.Value

local casing = humanoid.Parent.animSyringe.Casing
local plunger = humanoid.Parent.animSyringe.Plunger
local needle = humanoid.Parent.animSyringe.Needle
local serum = humanoid.Parent.animSyringe.Serum

local player = game.Players.LocalPlayer

local healing = 30
local canHeal = false
local coolDown = true
local keyBind = "f"
local mouse = player:GetMouse()

mouse.KeyDown:Connect(function(key)

    if key == keyBind then

        if stims > 0 and humanoid.Health + healing <= 100 and humanoid.Health < 100 and coolDown == true then

            canHeal = true

        end

        if canHeal == true then 

            casing.Transparency = 0
            plunger.Transparency = 0
            needle.Transparency = 0
            serum.Transparency = 0

            local animation = humanoid:LoadAnimation(script.Animation)
            animation:Play()

            wait(animation.Length)

            casing.Transparency = 1
            plunger.Transparency = 1
            needle.Transparency = 1
            serum.Transparency = 1

            if humanoid.Health + healing > 100 then

                humanoid.Health = 100

            else

                humanoid.Health += healing

            end

            stims = stims - 1

            canHeal = false
            coolDown = false
            wait(10)
            coolDown = true

        end

    end


end)