There are literally dozens of mentions of the lips of various spice-using characters in original six books of the Dune series by Frank Herbert, short stories and follow-on books by Brian Herbert. Lips are licked, curled, pursed, pouted, patted, parted and wetted on a nearly clockwork basis but none of these mentions are accompanied by any suggestion that the lips are blue or have taken on the same blue tinge we see in the eyes of spice addicts.
The OP may be mistaken for Suk Conditioning which seems to turn the lips a dark purple colour (Yueh is frequently described as having dark or purple lips) or Mentat Conditioning which is often accompanied by heroic consumption of Sapho juice which turns the lips a vivid red colour.
Original Book series (Frank Herbert)
The closest we get to a description of lip colour is in Dune Messiah where we see a description of Korba's lips turning "white with fear", a coloration that would be impossible if they were blue.
It's also worthy of note that in Children of Dune, Farad'n has managed to conceal his spice addiction with the artful use of contact lenses. Obviously this would not be possible if there was a substantial discoloration of the lips:
Farad’n touched his own eyelids, feeling the hard surfaces of the
permanent contact lenses which concealed the total blue of his spice
New Book Series (Brian Herbert)
In Paul of Dune we see a Fremen warrior who has nearly drowned
Enno was completely limp, not breathing. His lips were pale blue, his
skin clammy, his eyes closed.
again, this would be consistent with normally coloured lips in a person who had drowned.
Other non-canon materials
The Dune Encyclopedia (considered canon at the time of writing but since de-canonised by Frank Herbert's son) makes no mention of blueing of the lips in its list of symptoms of melange ingestion.
- There is no blueing of the lips in the made-for-tv adaptation
- There is no blueing of the lips in the feature film