[Rilgamon]

I've changed it a little so it works without your UI and both bars show up like they should.

local Experience = CreateFrame("Frame", nil, UIParent)
 
local ExperienceBar = CreateFrame('StatusBar', nil, UIParent)
local ExperienceBarRested = CreateFrame('StatusBar', nil, UIParent)
 
local InvisFrame = CreateFrame("Frame", nil, ExperienceBar)
InvisFrame:SetFrameStrata("HIGH")
InvisFrame:SetFrameLevel(5)
InvisFrame:SetAllPoints()
 
local ExperienceFont = InvisFrame:CreateFontString(nil, 'OVERLAY')  
 
local function UpdateExp()
    local Current, Max = UnitXP("player"), UnitXPMax("player")
    local Rested = GetXPExhaustion()
    local IsRested = GetRestState()
    
    ExperienceBar:SetMinMaxValues(0, Max)
    ExperienceBar:SetValue(Current)
    
    if (IsRested == 1 and Rested) then      
        ExperienceBarRested:SetMinMaxValues(0, Max)
        ExperienceBarRested:SetValue(Rested + Current)
        ExperienceFont:SetText(""..Current.." / "..Max.."("..Rested..")") 
    else
        ExperienceBar:SetValue(0)
        ExperienceFont:SetText(""..Current.." / "..Max.."")
    end
end
 
ExperienceBar:SetPoint('CENTER', UIParent,"CENTER")
ExperienceBar:SetStatusBarTexture("Interface\\TARGETINGFRAME\\UI-StatusBar")
ExperienceBar:SetSize(235, 18)
ExperienceBar:SetStatusBarColor(0.6, 0, 0.6)
--[[ExperienceBar:SetBackdrop({
    bgFile = AftermathhUI.media.blank,
    insets = {top = -1, left = -1, bottom = -1, right = -1},
    })
]]--
--ExperienceBar:SetBackdropColor(unpack(AftermathhUI.media.backdropcolor))
 
--CreateBorderLight(ExperienceBar, AftermathhUI.media.bordersize, AftermathhUI.bordercolor, AftermathhUI.bordercolor, AftermathhUI.bordercolor, 3)
 
ExperienceBar:EnableMouse()
    
ExperienceBarRested:SetSize(230, 18)
ExperienceBarRested:SetAlpha(0.5)
ExperienceBarRested:SetParent(ExperienceBar)
ExperienceBarRested:SetAllPoints(ExperienceBar)
ExperienceBarRested:SetStatusBarTexture("Interface\\TARGETINGFRAME\\UI-StatusBar")
ExperienceBarRested:SetStatusBarColor(0, 144/255, 1)
 
ExperienceFont:SetFont("Fonts\\FRIZQT__.TTF", 12)    
 
 
Experience:RegisterEvent("PLAYER_XP_UPDATE")
Experience:RegisterEvent("PLAYER_LEVEL_UP")
Experience:RegisterEvent("UPDATE_EXHAUSTION")
Experience:RegisterEvent("PLAYER_ENTERING_WORLD")
Experience:RegisterEvent("PLAYER_UPDATE_RESTING")
 
Experience:SetScript("OnEvent", UpdateExp)