What does “Make S_ItemDetails” do?
I followed this series by Epic to do a simple point counter.
It was the fourth or fifth one where you promote your player or what it was to a variable and the widget then poll’s that for the value.
You could also make a simple counter or something alongside your health packs to test and debug the issue more easily as there are fewer things to go wrong.
Have you tried using breakpoints on the nodes to step through the flow to see what is happening?
Possible problem is the converting of your item to string for display.
HTH