My Dr told me to carry on using nitro for 8 weeks - even if I thought I was healed before that. My instructions were to apply it internally with a gloved finger - apparently this minimises headaches too. I bought some disposable latex gloves & I just cut one finger off them when I need (I've got long nails!). I do get a bit lightheaded & a strange taste in my mouth after applying but nothing on the headache front.
Prior to my recent little re-tear I had felt a definate improvement by week 3 from unbearable spasms sitting down or lying down at night (I was only OK standing) to just mild discomfort. I'm going to carry on for the full 8 weeks & as long as things continue to slowly improve, ask to stay on it for longer !
Bliss