Splint and elevate. Splits that hold the hand in the position of function (holding a soda pop can) achieve rest that may minimize the tendon swelling. Elevation of the hand particularly at night combine with short term anti-inflammatories may help.
Distal joint splint. Don't over treat i.E splinting the distal joint (so-called dip) is enough along possibly with anti inflammatories and localized massage. If you over treat you can end up with unnecessary finger stiffness.