1: Check for alternative names. Many volcanoes have multiple names and I've tried my best to eliminate duplicate listings from the volcano repository.
2: Does your volcano have a psuedo-prefix such as Mt, Cerro, or Sierra? Most of these psuedo-prefixes have been dropped, but some less common ones are hanging on ...such as indonesian volcanoes where it can be difficult for most of us to distinguish whether the first word is part of the name. Try looking for your volcano with and w/o the first word.
3: Try checking the regional listing. It may be easier to find on that page.
4: Finally, it may simply be missing. If you are certain that this is the case, contact me with the name of the volcano, any information on it you can provide, and references published or webpage format. It will be added when I establish that it is a factual volcano that has not yet been listed in the repository.