My 11 Week Old, Woke Up From Nap This Am,

My 11 week old, woke up from nap this am, with mottled skin of both lower extremities. It blanched white when pressed. Skin is its usual warm to touch. He slept in a short onesie, and wrapped in sleep wrap. He is acting very well, nursing, and alert. Now back to sleep, on his back, in sleep sack. Should I be worried? I observed this 1 time yesterday, then it was gone.