It sounds like possible Itch... Sorry you got some bad advice from the LFS
I would recommend an immediate PWC
Here is a write up on the disease: (You can find more info here -
http://www.tropicalfishcentre.co.uk/Diseases1.htm)
Ich (
Ichthyophthirius multifiliis)
Symptoms: Salt-like specks on the body/fins. Excessive slime. Problems breathing (ich invades the gills), clamped fins, loss of appetite.
Ich, Ick, white spot disease, whatever the name, this is the most common malady experienced in the home aquarium. Luckily, this disease is also easily cured if caught in time! Ich is actually a protozoa called Ichthyophthirius multifiliis. There are three phases to the life cycle of this protozoa. Normally, to the amateur aquarist, the life cycle is of no importance. However, since Ich is susceptible to treatment at only one stage of the life cycle, an awareness of the life cycle is important.
Adult phase - it is embedded in the skin or gills of the fish, causing irritation (with the fish showing signs of irritation) and the appearance of small white nodules. As the parasite grows it feeds on red blood cells and skin cells. After a few days it bores itself out of the fish and falls to the bottom of the aquarium.
Cyst phase - after falling to the bottom, the adult parasite forms into a cyst with rapid cell divisions occurring.
Free swimming phase - after the cyst phase, about 1000 free swimming young swim upwards looking for a host. If a host is not found within 2 to 3 days, the parasite dies. Once a host is found the whole cycle begins anew.
These three phases take about 4 weeks at 70º F but only 5 days at 80º F. For this reason it is recommended that the aquarium water be raised to about 80º for the duration of the treatment. If the fish can stand it, raise the temperature even higher up to 85º.
The free swimming phase is the best time to treat with chemicals. Raising the aquarium temperature to 80º F will greatly shorten the time for the free swimming phase to occur. The drug of choice is quinine hydrochloride at 30 mg per liter (1 in 30,000). Quinine sulphate can be used if the hydrochloride is not available. The water may cloud but this will disappear. By reducing the time (with raised temperature) of the phases, you should be able to attack the free swimming phase effectively.
Some aquarists like to use malachite green, but it tends to stain the plastic and silicone in the aquarium. Most commercial remedies contain malachite green and/or copper, which are both effective.
A word of warning with using medication: Obviously people want to save their fish, so they go and buy a product, and sometimes these can be quite effective. But a word of warning - some meds can be very detrimental in the long term. Treatments whitch use Malachite Green and Methylene Blue can be useful treatments for parasites and Fungus, unfortunately they can destroy our beneficial bacteria, and then you can get a Ammoni/Nitrite peak for some time. Also some meds demand it that they remove Carbon/Zeolite for the duration of the treatment - this can effectively start up a mini-cycle as the Carbon/Zeolite have lost their bacteria.
Salt bath: So a salt bath is a good way of treating the fish without damaging the bacteria we need. It is a good antiseptic and fungicide. If you are using high doses, its best to try to gradually raise the concentration, so the fish don't become stressed. Sometimes it can be effective to use a short salt bath, with higher salt concentration (such as fungal infection - 10G/Litre for 30 min). 
