ENS names will update instantly on the ENS app, however third-party sites like OpenSea have less frequent database updates.
That said, you may be able to prompt the refresh of metadata on individual names.
OpenSea's Refresh metadata
Instructions
Go to your ENS name on OpenSea
If you're having difficulty finding the name, here's a tool with quick links to locate your name on sites like OpenSea: tools.ens.domains/check
Select the 3-dots (top right hand corner)
Click "Refresh Metadata"
Updates take anywhere from a couple minutes to a few hours.
More Information can be found in our Opensea Article including links to OpenSea's support if issues persist for more than 24 hours.