Does using Minoxidil on a hair transplant area 3 months post op make the hair growth results appear sooner?

Hair follicles will often enter a dormant, or “telogen,” phase after the shock of being transplanted, and shed their existing hair strands before cycling into the next stage of regrowth. This is perhaps the most common reason for temporary “shock loss” and why it may take several months before the results of a hair transplantation procedure are noticeable. Because minoxidil works, in part, by encouraging those follicles to re-enter the anagen (or growth) phase and to stay in that phase longer, it absolutely could make results appear more quickly after you have healed from your hair transplant procedure. However, it is important to remember that different patients can respond to medications differently, so individual results may vary. As with any medication, you should discuss with your doctor whether it is the right course for you.
More importantly, most forms of hair loss are progressive and hair transplantation only moves healthy hair follicles into thinning areas; it does not prevent further hair loss from occurring. This means that a patient who does not use some form of hair loss prevention will most likely grow dissatisfied with their hair restoration results. Even once the newly transplanted follicles begin to grow, if something is not done to prevent the older surrounding follicles from failing there will either be no improvement or a noticeable loss of overall thickness. This is why we generally recommend, at minimum, that patients adhere to a regular regimen of 5% minoxidil and/or finasteride, and in some cases may combine that with other prescription medications, depending on the patient’s individual needs. While minoxidil may help you see results more quickly, it is really more important as a part of an ongoing hair maintenance plan.

At this point, no, it probably wouldn't make any difference in the results of your hair transplant procedure. It definitely wouldn't hurt though, and would likely help your natural hair grow thicker which would improve the appearance of your hair overall.