Being the only hand up on the vote is lonely for a minute and honest forever.

Being the only one in a room voting the other way is loud for about a minute. What you keep afterward is a clean memory of what you actually thought, which outlasts the discomfort of that minute by a long way. Groups quietly respect it too, even when nobody says so at the time.

If you are the lone hand, keep it simple and unaggressive. Give your reason once, then let the vote happen and do not campaign afterward. And do not decide you were wrong purely because you were outnumbered.