Redness decides when you can be seen in public again, so it is the first number to learn before you book microneedling. Two dermatology sources give a window and they agree on its shape.
The American Academy of Dermatology on the first days
The American Academy of Dermatology describes the immediate aftermath: "Immediately after microneedling, you may see some redness (lighter skin tones) or darker shades (darker skin tones) on your treated skin. Your treated skin may feel like it’s sunburned, causing minor discomfort, burning, or swelling. These reactions usually disappear in a few days to a week."
The Society's shorter version
The American Society for Dermatologic Surgery is shorter on the point: "After the procedure, there can be minimal swelling and redness for several days, but there is little to no discomfort."
Putting the two windows side by side
Both say several days. The American Academy of Dermatology stretches the upper end to a week, so use a few days as the best case and a week as the number to plan around.
Checking it against your calendar
Look at the week after your appointment. If an event falls inside it, move the booking rather than gamble on the short end.
For wider reading, see the Society's microneedling page, the Academy's piece on microneedling fading scars and uneven skin tone, and a PMC systematic review of radiofrequency microneedling for facial rejuvenation.
The cost behind the redness
A few red days is the cheap part. The expense is the series of visits, so allow for a recovery window each time.