I am not familiar with any treatment directions on this product, but the similar Proform-C recommends a 25% water change before each of the three treatments, not after, as the treatment takes some time to become spent, and a water change would just dilute the treatment. I don't know if the fishes behavior is continuing or not, but it is fairly common for a fish to exhibit some distress with the treatment as the parasites try to burrow deeper to get away from the chemicals that are trying to kill them. This is generally very temporary, lasting just a short time before those parasites are dead.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard