The sauna in your gym is the one I would recommend. It opens up the pores in your skin.
The toxins released in Liver-Flush wouldn’t “float around” in you body for two weeks after the flush. I would probably do another Liver-Flush in week’s time and discontinue those herbs for 2-3 days while doing the flush. See what happens to you skin?
During that time it may become clear if those herbs are the cause of the skin tone.
If not, you can continue them normally.