I would suggest you to take medicine coz tampons might be really risky.Once my sis's friend used it and when she wants to remove it, the string connecting to the tampon broke and she have to go to hospital to remove it...so it's kind of dangerous !!

I used to take the period delay medicine twice.Once during trip to Pangkor island and another is at camping in the wood during National Services...and after a month or two, I had my punctual menstrual again. no mood swing,no acne but a lil weight gain for sure, bcoz it's a hormones medicine.

Anyway,if you still confused on the usage, you might go to those pharmacies and consult theirs opinion for secure.
Enjoy ya holidays !!