Baytril can cause TISSUE necrosis. never heard of anything with the muscles. Subq is a good way to get Baytril "Burns" in my opinion. Diluting with Saline is also a good idea when using the 100mg/kg Baytril, but for the 22.5mg/kg, I've found a lot of people don't bother.
BEST way to prevent scarring is to inject it DEEP into the muscle and then rub the site to disperse the medication.
I give any medication when needed for a full month.
This is just my experience and by no means should go past your vets orders. But in my experience, most vets are clueless about herps and knowing a thing or two can sometimes be very beneficial.