Try the inositol-hexanicotinate version. I get it from CVS. It's inositol bonded to 6 molecules of niacin. It enters the bloodstream and slowly breaks off the bond, so you don't get nearly as much of a histamine release, which is what causes the burning sensation. Also try taking ascorbic acid along with it. Niacin releases histamine, and vit-c destroys it. Taken together they balance out histamine levels. Vitamin-c is also an anti-fungal, antibacterial, and boosts the immune system. All of this helps to get well, as lyme sufferers usually have immunocomporization and resulting co-infections.
I take 1 gram of INH along with 2 grams vit-c 3 times daily. I originally started with 1 gram each, but bumped up the vit c. You may want to try 500 mg of each, three times a day initially. After a week, if there's no major side effects, bump it to 1 gram each 3 times daily.