Thanks for writing to hcm forum.
Depo-provera shots can lead into depression/anxiety and thereby can cause canker sores .
I would advice you to take steroids
aft.er consulting with a physician.
Maintain oral hygiene
Take vitamin becosules
Balanced diet and fluids has to be ingested.
Please do consult with your physician and get the depo-provera replaced by other methods/devices.
Hope this helps.