I don't think there's any reason why you couldn't do the massage now, but I really don't know if it will help. I've heard taking vitamin E can be beneficial. It is supposed to improve skin elasticity. Having a warm compress applied to the perineum at crowning to support the skin, and help it relax can help. They did that for me with DD1, and it felt SO good, and I didn't tear. You might want to look at water birth, if it's an option where you live. Birthing in the water is also known to reduce tearing.
Talk to your OB/midwife about your options, and let them know that you REALLY want to avoid a tear. On your birth plan, make a note about being reminded to pant and breathe the baby out, rather than pushing at the end, and ask that anything possible be done to avoid tearing.
All the best!