They are available in drug stores and are quite cheap.
 According to Marcia Steward at the ILCA conference, New Orleans, 1997:

Guidelines for using a Hydrogel:
* wash hands before handling
* cut dressing 1/4 - 1/2" larger than wound
*  remove the backing from dressing
*  aply the gel side to wound
* use breast pad in bra to hold in place
* REMOVE dressing for nursing, place it on a clean surface, gel side up
* use a new piece of dressing every 1-3 days or as needed
* there is NO need to wash breast before nursing
* consult health care provider as necessary

You can find the complete (excellent) session from Marcia in the Track 1,
sore nipples set of tapes available from Repeat Performances, (219)
465-1234.  It is tape D of this track.

Terriann Shell