Begonia leptoptera H.Hara, J. Jap. Bot. 48: 98 1973.;

Nepal as per WCSP;

SK807 17 OCT-2017:ID : 18 posts by 3 authors. Attachments (9)- around 800 kb each. 

Location:  Kharidhunga, Sindhupalchok, Nepal
Date: 6 September 2017
Elevation : 8700 ft.
Begonia … ??????

Pl. check with comparative images at Begonia 

Some Begonia sp. 

Kindly consult local Flora.

Closest I can go as per comparative images at Begonia is Begonia picta Sm. only.

Thank you …

… has suggested this entry as Begonia rubella Buch.-Ham. ex D.Don.
I guess need further investigation to validate the  ID.

To me also appear close to images of as suggested by … (though flower arrangement looks a bit different) as per the following:
What are the exact words of …?

Reply from …: Not sure – B. rubella?

I am not that familiar with the begonias of Nepal but after sharing photos with … we think it is possibily Begonia leptoptera.