If you have lost your vaccination card or don’t have a copy, contact your vaccination provider directly to access your vaccination record.If you cannot contact your vaccination provider directly, contact your state health department’s immunization information system (IIS). You can find state IIS information on the CDC website. Vaccination providers are required to report COVID-19 vaccinations to their IIS and related systems.If you enrolled in v-safe or VaxText after your first vaccine dose, you can access your vaccination information using those tools.
If you have made every effort to locate your vaccination information, are unable to get a copy or replacement of your vaccination card, and still need a second shot, talk to a vaccination provider.

https://www.cdc.gov/coronavirus/2019...cond-shot.html