I have this spot on my toe. I thought it was a mosquitto bc it itched bad w no color. Now its dark red almost purple. Not a blister. Above nail bed.

Does your dog bite ? It still could be a bite of some sort. You are seeing a localized inflammatory reaction to a foreign protein possibly being introduced to your toe. There is dilation of the blood vessels and possible sub-dermal bleeding. Warm compresses may speed the resolution of the condition. If there is no improvement soon then it would be best to see your doctor.