Can say Fissure in ano only when ulcer develops in anal mucosa.
Any wound outside anus will be deferent problem. It may be due to trauma or fungal infection. Consult with skin specialist also.
LIS doesn't give prevention for future recurrence of fissure in ano. It's method to help in healing of present anal fissure only.
Next Steps
for symptomatic problem, you should consult surgeon/dermatologist timely.