Keep the receipt or invoice, and submit proof of payment to your insurer once the workers comp claim has been approved.
If you sustain a workplace injury or illness, you should seek medical assistance as soon as possible.
Since it is highly unlikely for your workers comp claim to be approved so quickly, it is important to keep records of medical bills and treatment records for a hassle-free reimbursement process.
Be sure to keep the receipt or invoice for any injury-related medication prescribed by the GP as well. As long as the medication is related to the injury, once the claim is approved, you can submit proof of payment to your case manager for reimbursement.
Taking a photo of receipts or invoices is a good practice for documentation in general.