The treatment should continue usually for at least one week after ALL the symptoms disappear. Vacuuming is definitely helpful but not necessary IMO, unless the fish is doing really poor. The salt at ~2-3 (from 1 to 5) teaspoons per gallon kills the larvae in the free swimming stage completely interrupting the life cycle of the parasite.
A word of warning though: ich never happens for no reason. Reason #1 by 99.9% is stress - rehoming, bad water, wrong water, not enough oxygen, aggressive tankmates, inadequate temp, unstable water params/temp, improper WC's, some other prior bacterial/viral/parasitic desease, etc.
Most usually when the root cause is not identified and remedied, the ich treatment is not successful. For instance, secondary bacterial infections will ensue (inflammations... like the redness in your case) etc. - a symptom that the fish's immune system is unraveling as a result of the root cause and likely that the root cause has not been resolved (that is, if the ich treatment has been applied correctly).