What should stores do when handling customer allergy feedback if the beauty product batch number cannot be found today?

Today, our store received allergy feedback regarding a body care product. The customer only brought half a bottle, and the outer packaging was missing; the front desk couldn't find the batch number at first. We first asked the customer to stop using the product, took photos of the bottle, the remaining texture, and the purchase record, and then traced the lot number of the same SKU purchased on…