Try the Singapore international forum. Read the rules post first.
To be honest I am hesitant to suggest ANYTHING if you are only going to be there 8 days. IDK if nicotine replacement is illegal in Singapore, but if it's not, I might go that route. If it is (it may well be, SG seems to WANT everyone to smoke) I might be more likely to pick up a pack of cigarettes.
If you get caught, it's possible your vacation costs may double, triple etc., and also, your vacation stay may be longer than you desire. I'm not kidding about how voraciously SG "enforces" its policies.
But if you must take the risk, head over here:
SG Vapers
Read the rules post, and good luck. Welcome to ECF.
Anna