How to treat flea bites will vary according to the severity of the bites.
Fleas like to gang up and continually feed from the same area on your Golden Retriever, until the skin becomes swollen, irritated, and possibly turns into an open wound.
If this open wound becomes infected, then you will need to see your vet and get antibiotics, as an actual infection will not heal on its own.
If it is not infected, there are a few different products you can treat it with, to help it heal faster.
Peroxide, applied with a cotton ball, can be used.
Bactine is also good for small cuts. I prefer the liquid rather than the spray, but either one will help.
Bag Balm is another great product. This is very thick, almost like petroleum jelly, and is used for healing small cuts.
Another option is to allow the area to simply heal on its own, without applying any products to it.
The best flea bite treatment for people is to simply not scratch it!
Scratching the area actually causes the bite to swell more, which in turn, causes more itching.
Unfortunately, the bites will flare up and itch many times over the course of several days, before it goes away completely.
Hydrocortisone creams will relieve the swelling and also the itch and will probably need to be re-applied several times.
Killing fleas on dogs needs to be a top priority as it does no good to treat the wound, if the fleas are allowed to keep coming back and re-opening it, or start a new area to feast on.
They will keep returning until you break their life cycle, which can be easily accomplished with the proper preventatives.