I am very fond of Yerba Mate. I had not read that it helps with acne--interesting to know. I have found that help my mood though.
I am not sure what instructions you read. I know that you should not use boiling water. Like green tea you want to use hot water. Usually I turn off the heat as soon as small bubbles start to form at the bottom of the pot. I would suggest seeping it for 5 minutes. I usually seep mine for 10 to get the most flavor out it. If you don't have time to wait for it to seep just take it in a mug with you maybe.
Yerba Mate is the only tea that has enabled me to staff off of coffee in the morning. It is energizing.