What kind of flea collar? Is the dog inside or outside? If outside at a box you will also likely need to treat the dogs pen and box to get rid of them.
Up to you but I haven't ran into any of those nasty critters, ticks, fleas, mites, lice, mosquitos, that have a stomach for a good permethrin based product.
I use the Freedom Spot on 45 for direct use on the dog. You can get it packaged for dogs, or do like I do and buy the ones packaged for horses as it's cheaper per ounce, then I just dose at dog dose. But even buying it packaged for dogs it just cost a little over $2 per dose and it lasts for a month per dose. 1.5 cc's for a dog under 33 lbs. 3cc's will treat a dog 33-66lbs. Over 66lbs is 6 cc's. Put half of the dose between their shoulders, the other half from between their hips down to the base of the tail. Because I buy it packaged for horses I put 3cc's into a 3cc syringe without the needle of course, and use it as an applicator to get it down through the hair and on their skin. If you buy it packaged for dogs you of course just use the pre-packaged applicators.
If your dog has that many fleas, then the area it spends a lot of time at is probably infested and will need treated. You will want to look for something along the lines of this.
http://www.domyownpestcontrol.com/pt-ultracide-20-oz-p-175.html
