Sprained my back and going for TCM massage. Can I still breastfeed with those herbal oil applied?

It depends on what kind of oil the masseur is using, do let him/her know that you are breastfeeding. All registered TCM practitioners will know how to properly prescribe herbal medicine to pregnant/nursing women. They will know which herbs must be avoided, and how to combine and process others to moderate or enhance herbal action, thus making them perfectly safe for mommy and baby. TCM is an ancient system of medicine which has withstood the test of time and it is generally extremely safe, effective and with very rare side effects.