Hi
I have acupressure metal balls taped behind my ears (I need to massage them - for helping with weight loss… ).
They will remain on for next 9 days. Then they will be replaced with new balls in a new location behind ear.
Is it permitted to walk out of an eiruv on shabbos ?
No.
I think that the original poster was talking about something like this:
https://www.austinmedical.com/ac800npmag.html?utm_source=ac800npmag&utm_medium=shopping%2Bengine&utm_campaign=googleproducts
I have had similar; they are small and slight and are attached/worn more like a bandage than anything else.
I don’t know if that makes a difference. 
Also no good.
Okay cool. Is the deciding factor whether the majority of people would use it in the form of “wearing”?
It’s not about majority, it’s about whether this is something that is normally worn. Taping something behind your ears is not what we would consider normal to wear.