The End is Nitrate the nitro help with the spams about two weeks after I started, but didn't heal the fissure right away, it wasn't until 4 months later and pushing that I got spams free, my doctor told me to use it as long as needed.
Now after 4 months I developed a rash that then blistered so I had to stop, plus a yeast problem, thats when I started to blow dry the area also, you will find as you read threads and post that members here had tried almost everything to get this problem under control. :D
I developed my own care after trial and error, plenty of Vaseline before a BM, to ease the irritation and pain, then after the BM, sitz bath, after the sitz bath I use and still use a Carlson suppository and another before bed.
This is how I have been healing since month 6 when my doctors manipulation of the fissure and sentinel pile caused me my last major retear, keeping the area lubricated has been the major factor on making the all day pain and irritation better.
And after talking with my doctor about surgery in Feb, he said that he will not remove the skin as it's just skin, some doctors have not problem removing it, I opted for more time to see if the fissure heals by itself and so far so good, my next app is on June.
Now I have to say that mine has receded a lot and that my anal area looks almost normal again.

Here's a natty suggestion when it comes to applying nitro, I tried it today after a eureka moment!
As said, I've been smudging it around my bum hole and not being able to tell if I've hit bullseye or not. I thought about a q tip cotton bud covered in cling film to act as a semi applicator but didn't fancy the bathroom acrobatics and contortionism with a mirror! Then it dawned.. I went to my pharmacy to buy a syringe (without a needle) (cost 89p) sold to dispense children's liquid medicines. I pulled out the plunger and inserted my 2.5cm dose plus 0.5cm which wouldn't be totally pushed out by the plunger down the 0.5cm neck. I reinserted the plunger and pushed the ointment down ready to dispense. I pop the little 0.5cm neck into my bum hole and administer a neat 2.5cm right in, no spill onto sentinel pile or smearing elsewhere. After removal, the 0.5cm of remaining ointment is still in the neck so I can be absolutely sure of dosage. The syringe comes in a sterile pack and I can also sterile it for next time too. Very happy! (Even with the headache!)

The instructions on my box say it should be placed around an inch inside. You do get used to using a finger, it's only your own body at the end of the day... nothing to be embarassed about.
However if it relieves the spasms and works for you then I think its a good idea. Healing is all that's important at the end of the day :)

The End is Nitrate like you I also felt that I wasn't using enough of the nitro, so what I did was to put the bit of nitro on a tip of a Q-tip and gently pushed into the area.
Once the sphincter irelaxedxe with the cream it becomes easier to do.

Hi Crackin and Marg- thanks for your replies.. It's not that I'm squeamish about a finger up the bottom, it's anything up the bottom! I thought of the syringe purely because it could be more accurate for dispensing into the bottom, isn't as wide as a finger nor does it have nails! A q tip is also a good alternative too. Keep up the good suggestions :)

Bit of an update- it's a week tomorrow since AF diagnosis and nitro ointment prescribed. I'm already feeling so much better :) I've been administering the nitro with a medicine syringe to avoid smudging nitro on surrounding skin and making sure I get an accurate hit! It's working well and I can comfortably and conveniently insert it without mess or making weird straddles over mirrors! I've been tailoring my diet to more soft BM producing foods and completely steering away from higher process foods and white bread and rice etc. Innocent smoothies are my new best friend too - love them! I've been having one movicol/miralax a day as well as a daily sitz bath. My BM's are softer, and pass more freely and already, hardly any pain. No blood on tissue either. Drawbacks are fuzzy headaches after nitro (worse in day, easier to deal with by night) but its manageable if a bit annoying and a bit of palpitation feeling but not worryingly. I'm still in shock at how quickly side effects occur after application...within 1-2 minutes! I'd rather the headache any day over AF pain. If this is the result at barely one week, I'm hopeful for proper healing long term without other interventions. Keeping them all crossed! Hope you are all doing ok too x