Sore throat: Reddishness in the throat (on tonsils, fauces and soft palate)

Good evening,

Last week Sunday I got a sore throat with reddishness in the throat: on tonsils, fauces and palate). From Monday onwards cold, cough and mild fever. Tested negative for the ongoing virus.

I have used Merc. Sol 30 3D for five days; it has helped me with feeling completely but the reddishness has not completely gone. On the tonsils it is still red. On the fauces, now I see white spots in between the reddishness. One ulcer on the right tonsil.

Will it go away in a while or do I need to continue Merc. Sol 30 or move to 200 or switch to another remedy?

Following are further details:
- Feeling cold, feel better when steaming or in hot shower
- wet cough more during the morning,
- BP normal
- No temperature
- Mild fatigue in the mornings
- Medium built constitution: legs emaciated when compared to the upper body
- Flat feet issues
- Digestive trouble when I eat raw onions, or post antibiotics use

Historical treatment of Sinus, Bronchitis, Hemorrhoids using homeopathy.

If you need further details appreciate the link to the questions, I didn't find the thread where the details required to share for the case taking.
Thank you in advance and good evening.