You should declare it upon entry to Chile, and let them see it. If it is in tea form I doubt they will give you a hard time. If they do, just surrender it and no problem. However, you might want to ask some people from Chile if you can actually get it there, it would be a waste of time, and money, mind that you will be paying airport prices, to buy it in Peru if you can get it in any Tottus or Santa Isabel.