Hi Selinas Mum and welcome!
It is saddening to hear that such a young child has to endure something as horribly painful as an anal fissure... :(
When you first log on, and you are at the home page, you'll see the main listing for the boards on the forum, the first being
"New to the forum? Introduce yourself here." There you'll see all the various subject for the board. Click on the first one, then look for the small blue "New Topic" button with the sun on it. Voila, you are starting a new thread, and remember to give it a title!
I really cannot recall anyone here for a child under 10, or even much older, but I sure could have missed it. But AF in kids is certainly not rare. What does the prescribing physician say about her using the rectogesic at her age -- THAT would be the advice to follow? I am sure, that, medicine aside, many of the more conservative treatments you'll find discussed on the MANY threads here will apply to Selina.
For instance, what is her diet like? Children should heal easily and quickly unless there is some other underlying and unaddressed issue. If the junk food is cut out, and no large amounts of meat and starches are eaten daily, AND (especially) she eats plenty of SOFT COOKED veggies and fruit each day, regularly, that should go a long way in creating a soft, smooth, WET stool which is key to bringing the pain levels down and healing.
She needs blood brought to the area to help it heal. Warm, (really, fairly hot) soaking baths will give her relief AND bring blood to the fissure site to help it heal. If she is having the burning sensation right after the BM, the hot baths will be a BIG comfort.
I don't know how familiar you are with AF and treating it, so here's a good starting link if you need it:
http://anal-fissure.org/general-anal-fissure-discussion-f2/i-have-an-af-what-should-i-know-t1849.htmWe are here to help with any specific questions...