How soon after a facelift would you recommend microcurrent if at all?

Microcurrent therapy is not a well established nor scientifically proven therapy.  All plastic surgeons want the best results for their patients, so if microcurrent therapy really worked to maintain results, all plastic surgeons would use it or recommend it.  I know of no plastic surgeons who use it or recommend it.  However, should you decide to use microcurrent therapy, 3 months is adequate time for healing  and no harm should occur. 

Microcurrent should be very safe to do 3 months after a Facelift.  Whether or not it will be effective is another story

The benefits of microcurrent therapy are difficult to quantify and therefore it is difficult to provide you with any definitive recommendations. I would certainly consult with your surgeon first. and definitely avoid this for a minimum of 3 weeks. You must remember that while muscle bulk may provide some rejuvenative or volume correction, the repeated use of a muscle may result in secondary animation lines or wrinkles. It is for this reason that we use botulinum toxin.

There are no medical studies that support the use of microcurrent to improve the facial appearance before or after a facelift.

Microcurrent treatments have not been shown in any scientifically study I am aware of, to improve facelift results.

On the other hand I do not believe microcurrent stimulation of the facial muscles will harm your facelift results.

The Microcurrent tretaments of the upper facial muscles do not stimulate the SMAS which in the mid and upper face is fibrous tissue, not muscle that can be stimulated.

A word of caution-dynamic facial lines or wrinkles are partially caused by the repetitive contraction of the muscles of facial expression which  causes crow's feet, frown lines, and forehead lines. Muscle contraction also can accentuate Nasal Labial Fold Lines and Marionette Lines.

I have always wondered if microcurrent Stimulation of these facial muscles could WORSEN the lines of facial expression by exercising and repeatedly stimulating these muscles.

I'm not aware of any scientific study demonstrating the effectiveness of microcurrent on facial muscles. It will do no harm, 3 months after your facelift.