If and how you frame a painting depends primarily on your own preferences. Personally, I often like to leave pieces unframed. Sometimes the environment a piece is placed in (including nearby artworks) dictates whether a piece needs the refinement of a frame. A frame also can add a certain personality beyond what the artist may have envisioned. And, in many instances, frames protect the artwork surface or edges.
Encaustic paintings should not be covered by glass, but because the edges may be caked with overflow wax, it can be helpful to frame the piece with a FLOATER FRAME, one that does not touch the edge of the artwork, but protects the edges from damage.
Most of my encaustic pieces are done on 1/4" board, and usually cradled on the back of the board to prevent warping. Cradling also is necessary for attaching a FLOATER FRAME. These frames come in a variety of depths (rabbets), widths and in metal or wood. Many of my pieces are framed with a pewter gray metal FLOATER FRAME. A reputable local framer with an excellent visual aesthetic can help you make the frame selection that best enhances the artwork and also meets your specific needs.
Cradled back example:
Floater frame photos: