If your reactions are anything like what I've had in the past, you will first have a terrible headache followed by several rushed trips to the bathroom or, perhaps, constipation. Some other symptoms will return, but it's hard to say which ones since it seems a little different for each person each time. When it was really bad, my poo would turn yellow and my urine would have a strong smell.
It's not so different from a die-off reaction, but there are differences which can be figured out with experience.
Drinking a lot of water and going to the bathroom a lot are ways to reduce and eventually eliminate the reaction.