Panadol munching isn't a great plan for any more than a couple of days. If they aren't working, you should ask for a review to assess the site and your meds. That can probably be done over the phone with a bit of imagination. It's a time for innovation.
The old adage 'Everyone is different' couldn't be more true when it comes to mastectomy. There are a gazillion variants, but I'd be checking in to see if there is an underlying reason for the pain. I discovered I was an Olympic grade fluid producer, even after the drains came out. It was really uncomfortable, and required a few interventions. And better pain meds. Mxx