How long can I keep my tube of Mupirocin 2%; it has no expiration date.?

Check the bottom of the tube where there is a flat end, the flaps folded over should have the expiry date as an indent? That's where most expiry dates are. If you can't see it then please discard the tube. Manufacturers do not guarantee the quality or efficacy of the medicine past it expiry date and if you don't know what it is, then no point keeping it.

https://www.drugs.com/article/drug-expiration-dates.html