You retrain the same way that we told workers when we decimated the garment and manufacturing industries. You'll get the same amount of government support too.
Nowadays you'll be spending $40 (same price after adjusting for inflation) for something definitely not made in America, and probably of inferior quality too. Since the domestic garment industry has shrunk so much, the supply chains an economies of scale don't exist anymore to buy domestically-made garments of decent quality at those prices.
Well, it was, until the factories in Mexico also closed as the jobs migrated to China, Vietnam, and so forth. So Mexico got to enjoy the same problems America had, except they were poorer to begin with.