In a normal year the processing of an amended tax return will be 4 months or less. This is not a normal year due to the pandemic and limited staffing by the IRS to process paper tax returns. It may take much longer than 4 months to process the amended return.
Check back at least once a month on the IRS website for the status of an amended return - https://www.irs.gov/filing/wheres-my-amended-return
