How to upgrade weapons

[mikeg2k20]

I went through half the game wondering who I talk to in order to upgrade my weapons. The balms that you collect from chests cannot be directly used. What you need to do is

GO TO THE EQUIPMENT SCREEN
Equip the weapon you want to enhance.
Now press X (xbox) or Square on PSX to Enhance the weapon.

Each weapon can be Enhanced a max of 3 tiers.
Tiers can be gated by level.

Upgrades require some amount of Dew and a particular Balm.
Tier 1 = Dim
Tier 2 = Mysterious
Tier 3 = Exotic

You can upgrade main weapons and sub weapons.
However I wouldn't invest heavily into sub-weapons as they are weak overall.

I did upgrade the Staff of Occult Prime because it increases HEALING EFFICIENCY by about 60%. This makes your potions and heal spells extremely effective.