Seems like Doxy might be a better choice for the fall especially the way the seasons go in Massachusetts. However, if you just got a bite or diagnosed, Doxy or Tetra is a good choice and should start to kick the crud out of what ever is there. May take awhile. On the other hand it might not do anything. As you can see my answer is varied, just like Lyme.
The dollar spot fungus survives unfavorable temperature and moisture conditions in plant tissue and thatch as dormant, compact masses of mycelium, called sclerotia. Low nitrogen and potassium levels in the soil have been reported to increase the severity of dollar spot. Some rather severe outbreaks of dollar spot have been brought under control by the application of soluble nitrogen fertilizer. However, the beneficial effect of nitrogen is thought to be due to rapid recovery of the grass during periods of reduced disease activity.
With slow-release, you can go every six to eight weeks, depending on your watering, instead of every four weeks, Turnbull says. He recommends a slow-release that contains nitrogen but not too much. The most nitrogen you need on a lawn is one-tenth of a pound per week. The grass can't get any greener than that. If you use more, you're only going to make the grass grow faster so you have to mow more often, Turnbull says. The secret is to get it as green as possible without growing it fast.. Turnbull recommends giving your lawn between 2 and 3 pounds of nitrogen over the entire growing season. If you go with 25-0-4, that gives you 1 pound of nitrogen, so over four weeks, that's a quarter pound per week, Turnbull says.