Hi there @peachee80, I see you are brand new to the community. I'd like to take a moment to welcome you. I am sorry you are having so much pain.

Here is some research you may be interested in. Erosion has been reported in these surgeries, but not this soon.
Pyrolytic carbon humeral head in hemi-shoulder arthroplasty: preliminary results at 2-year follow-up: https://www.sciencedirect.com/science/article/pii/S2468602618300330

Pyrocarbon Humeral Head in a Shoulder Hemiarthroplasty: Preliminary Results at 3 Years Follow-Up and Review of the Current Literature: https://www.hindawi.com/journals/crior/2021/6633690/

Pyrolytic carbon hemiarthroplasty in the management of proximal interphalangeal joint arthritis: https://pubmed.ncbi.nlm.nih.gov/25708434/

Can you call the physician that referred you for the surgery?