It could be that the menthol in calmoseptine is not what your skin needs right now. Menthol worked very well for me in the first weeks, cooling and soothing, and creating a barrier against residue, but it became a bit too strong for me. I switched to Zincofax, a bum cream for babies' suffering diaper rash. Baby bums are always wet, covered with pee and poo, and locked against their skin with a thick diaper. Recipe for painful, raw skin. Same as a j poucher. Try Zincofax after every BM. Make sure your skin is 100% dry and clean before applying any cream, otherwise you risk a fungal infection back there. Use a cool hairdryer if you must.
To heal any abrasions hiding inside, or just for some relief from pain and burn, buy a sitz basin and use very warm water, sit in the basin once or twice a day for 10 minutes or until the water cools. You can use the tube that comes with a sitz basin to refil the basin with warm water without getting up from the toilet. The warm water will encourage good blood circulation to that area, and will soothe your burning painful skin. Zincofax is $10 or so at any drugstore's baby section.