Is it normal for the sore "look like aphthous" in vagina disappear suddenly without crust and peel ?

Could be herpes : Lesions which come and go and look like aphthous ulcers could be because of herpes simplex virus , usually they are also painful you need to see a gynecologist to get cultures for herpes and other stds you also must make sure that u avoid sex when u have lesions and that your partner uses condoms.

Possible Herpes: They can culture the lesion or do blood test to verify. Daily antivirals can reduce frequency of breakouts!