If you're getting a massage while massively congested due to a nasty cold (which, I reiterate for probably the thousandth time, I do NOT recommend), and not only do I considerately dispose of your nasty snot rags, but give you my very last cough drop, the least thing you can do is leave me a tip. Especially if, as you said, you LOVED your massage.
Thank you. Enjoy your flight back to Australia. Where they apparently don't tip.