The Biebs and Baldwin looked super chill and blissed out Tuesday evening as they waited for Hailey's ring to get resized inside Pristine Jewelers. Gotta say ... Justin's acing the fiance thing so far -- he gave Baldwin a shoulder massage while they were waiting.

She seemed reluctant to even briefly remove the ring. Still no word on the size or cost of her ring -- not that it matters. Hailey and Justin haven't stopped glowing since he popped the question this past weekend in the Bahamas.

We spoke with Avi and Ofir from Prestine who tells us JB also got a white gold ring of his own and picked up a white diamond encrusted Patek Philippe watch.