Forgotten Title I only remember one arc of it (BL)

This novel has been nagging me for the last two weeks, i still cannot find it I only remember one arc of, it is a trasmigration FOD like novel. As far as I remember this arc is in historical world. There is this cannon fodder who jump there and clash with 7th prince and his rebirth wife. He would be together with the crown prince. This mc detect his lover by looking for a specific mole on the his lover hand. At first the ori character kind of like this spoiled brat and then he become some sort like intelligent scholar when the mc come in. Plis help me :"" ive tried looking for this novel but atill no result (
Thank uu

 

That sounds a little like this one
There Will Always Be Protagonists With Delusions of Starting a Harem

 

Heroic Death System.
The mole on the hand thing is probably from this one.

 

It's Heroic Death System.... I read that one too )

 

Heroic Death System is probably the only one with a mole

 

Quickly wear the Face Of the Devil
It's the 3d arc
but there is no mole

for the mole (but at the hips)
There Will Always Be Protagonists With Delusions of Starting a Harem
but there not such story in this one