DataStore Issue : Date wont save?

CustomStore = game:GetService("DataStoreService"):GetDataStore("DataStore")
 
function PlayerEntered(player)

        local helm = Instance.new("StringValue")
        helm.Parent = group
        helm.Name = "Helm"
------------------------------------------------   
        if CustomStore:GetAsync("Helm_"..player.Name) ~= nil then
                helm.Value = CustomStore:GetAsync("Helm_"..player.Name)
        else
                helm.Value = "Really red"
        end
       
        helm.Changed:connect(function(Val)
                CustomStore:SetAsync("Helm_"..player.Name, Val)
        end)
------------------------------------------------
end
 
game.Players.PlayerAdded:connect(PlayerEntered)

This is my script. For some reason, it creates the string value, says "Oh. it's got a value already" (changed from "Really red" to "Really blue"), But won't save NEW changes?

anyone got any ideas?

local player = game.Players.LocalPlayer
function onClicked()
	player.Customisations.Helm.Value = "Lime green"
end
script.Parent.MouseButton1Down:connect(onClicked)

CONTEXT This is in a LocalScript, Inside TextButton, Inside a Frame, Inside a ScreenGUI, Inside StarterGui.