Just dropping this here. The queen is worried that Falma might lose his self because of the Medicine Gods blessing.

She explains that when she was a child, her leg caught on fire and the mark of the Fire Gods blessing was left on her leg as a burn scar. However, this mark was incomplete and part of it was not clear and just looked like a normal scar.

At the time, she felt horrible because it was ugly that a young girl like her had such a burn scar on her leg instead of a full emblem of the blessing. Still, getting the mark came with an immense increase in her magical powers and control of fire magic.

She says that she is now thankful it wasn the complete mark that she received, or else she fears her self might have disappeared as a result of the overwhelming power. She then worries that since Falma has the complete emblem of the Medicine God on both of his arms, he must have gained powers and knowledge that no human being can normally handle in their body. She is concerned that the blessing might have utterly destroyed Falmas self and that whats inside the body now is the Medicine God instead of MC.

Note: Remember that MC is a reincarnated person, and it is clear he died of some type of stroke due to overwork. Meaning he is still Falma. He is not the Medicine God, and is using his own knowledge as a professional back in his past life. Although he did get the blessing of powers (perhaps because he can do his modern-day medicine treatments without its help). The empress also doesn mention that she received past-life memories or any kind of personality altering change when she got her blessing.

There is a misunderstanding here because MC thinks she is talking about the Falma who was before MC reincarnated. If I understood the Japanese correctly from up until this point, I think the empress is actually talking about the Falma who cured her and talked her out of her self-contempt, which happens to be MC after he already reincarnated as Falma. This was the moment aside from the several months he was treating her that seems to have started to attract her to Falma (MC). This is also why she is saying If Falma(that I know) was sacrificed for the sake of the Medicine Gods blessing, then I will never forget him. Because of the attachment she has for him (MC).

The proof here is that the empress only first made contact with Falma during her illness arc. During that time, she clearly didn personally know who he was, meaning she has never had any direct knowledge of Falmas personality before MC aside from the fact that he was Brunos son (or perhaps she just saw the kid was an assistant back then).

However, the main purpose of this conversation was to further the mystery and conflict within MC if he truly is Falma in this world, or just a fake who stole somebodys body. Recall though, that early on in the story when MC first woke up as Falma, he realizes during dinner that he still has Falmas memories in him, becoming able to answer Brunos lecture questions despite MC not knowing a thing about the medicine practices of this world when he was asked.

I didnt expect the empress to have such a mark as well!

Oh...noooo....