Kordon is a good brand but when I treat ich, I usually prefer to use AQ salt and high heat. The instructions for Rid Ich say you continue to use it until cured so if you want to continue, you can. What size is your tank and how did you dose it? The instructions say to add 1 tsp per 10g . . .
Rufio could be darting because he's itchy or he could be darting because he's having trouble with the meds, it's hard to say. If you want to try to treat with AQ salt and high heat, you can do that too. You need to have an adjustable heater that will go up to 86 F though for best results. Do a complete water change to get the meds out and then add 3 tsps of AQ salt per gallon. Predissolve it in a little bit of tank water first.
If the tank is smaller than 2g, do 100% water changes every day and replace the salt. This is really important because it gets the ich parasites out of the water before they can reattach. If your tank is over 2g, do at least 50% and try to clean the bottom of the tank really well with a gravel vac.