You are correct to be concerned about this situation because whenever you hear the word "channel" it means contact with the occult. The concept of acupuncture is based on the belief that bodily functions are regulated by an energy called qi, but the idea of channeling this energy introduces another dimension to the equation. Acupuncturists normally apply fine needles to the skin's surface at key points on the body to allow the "chi" to flow through blocked channels or to redirect it into other routes. They don't typically "channel" it.
Channeling energy is more like what a Reiki master does when he or she actually allows the "energy" to flow through them into the patient under the direction of a "spirit guide" which is a spiritual entity of some kind (aka demons). This acupuncturist may be employing a combination of practices which is not surprising because there is absolutely no regulation or standards in the alternative medicine field. Practitioners can pretty much do whatever they want.
What concerns me is that whenever you get into the area of channeling or mediumship, you are opening yourself up to the occult and to the influence of occult powers. A medium typically serves as a channel for the spirits of the dead, and seeks to facilitate communication between these entities and the material world. This is also known as necromancy and is expressly forbidden by the Church because of the rather obvious dangers involved in consorting with hidden powers.
All practices that attempt to tame occult powers, "so as to place them at one's service and have a supernatural power over others - even if this were for the sake of restoring their health - are gravely contrary to the virtue of religion." (Catechism No. 2117)
In my opinion, you do not need to renew your baptismal promises because you had no intention of consorting with spirits when you visited this doctor. It is also obvious from your e-mail that you are concerned about having done wrong, and even went so far as to speak with your pastor about it. God sees the good will in our hearts and if it's obvious to me in just your brief e-mail, He certainly sees it too!
Personally speaking, if I were in your shoes, I would definitely go to confession and seek sacramental healing just in case. Better safe than sorry!
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