What are signs of an allergic reaction to face wash?

Yes, if it starts to peel, but also if it starts getting red anywhere else, if you break out, or it starts getting little bumps.

You have already mention the reaction and symptoms.
Better stop using that facial wash you have before it's too late.

It probably isn't an allergic reaction, but may be an indication that the scrubbing combined with the ingredients is too much for your skin. An unwanted side effect can be that your skin produces more oil to replace the drying effect of the scrub and your skin may actually break out more! The best advice would be to use the scrub intermittently, once a week or every other day if you feel like it is helping. It isn't a good idea to scrub your facial skin too vigorously with anything as you can cause little breaks in the skin which will then become irritated and red.