Firstly I would be very careful about long term genital use of dermovate. This is a potent steroid and can itself induce atrophy of skin generally. There are certain indications when it is used on the vulva but it is a bit concerning that you have used it for "thrush" for several weeks, on an already atrophic vulva.
Yes moisturiser contains "Linum Usitatissimum (Flax) Extract*, Aloe Barbadensis Leaf Juice Powder (Aloe Vera)*, Cyamopsis Tetragonolobus (Guar Gum)*, Ceratonia Siliqua (Locust Bean Gum)*, Sodium Chloride, Xanthan Gum, Potassium Sorbate, Citric Acid, Phenoxyethanol".
None of these are secreted by the human ovary.
I would restart the pessaries and use daily if you are able to insert them. If you previously used estriol cream with no issues, it would be reasonable to continue this, however if you have no prior use of this it may be that you are sensitive to one of the ingredients, and in your current delicate state it is not possible to determine if it would have burned anyway.
Also is there a reason you are using topical estrogen only? The bloodstream is nature's preferred way of delivering hormones to the genital tract and whilst topical estrogens have a role in pharmacological treatment, it can be difficult to achieve and maintain optimal results with the doses typically used, and is also problematic when there is a competing local skin condition affecting the vulva/vagina.
Given the length of time this has been going on and lack of relief it would be worth having a review with your GP or nurse.