Underneath sensor protection cover detached because of glue leakage

Guys,

One day I found black stuff on my arm and with little checking I found it was coming from underneath of my Gear Fit 2. I guess it was kind of glue that was holding the underneath sensor cover attached... because the cover also got detached... so since then I'm not using it as the sensors underneath have no protection now...

So what can I do now... I already have Gear fit 1 also which just decided to stop working one day and since then it is just dead liability I'm holding on my shoulders...

Thanks