Petra - I'm not an expert on this - hopefully someone will come along soon, but it's been my experience when cacti/
succulents have gotten burned outside that they usually green up again shortly after coming back inside.
I have one
plant in particular - a "flapjack" jade - that gets a very pretty bright red while outside in direct sun during the summer. A few weeks after I bring it indoors, it is all green again.
I'm not sure if that applies to all of them, and I do think that the christmas cacti are a bit more sensitive to the sun, so I would suggest keeping it in more indirect sun next time?
hmmmmm - I just read your response again - do you mean that they get the sun while indoors now? I grow mine in an east window - about 3 feet from the window, and it's been
growing strong for years now - knock on wood!
I just took this picture of mine - it started out as a 99 cent clearance
plant about 10 years ago from the grocery store - it had finished flowering then. Biggest problem I have, is that I cannot get any cuttings to root and form new
plants.
by the way... if your
plant is budding up now, you probably have a Thanksgiving
cactus rather than a Christmas
cactus - they are 2 different
plants, with different edgings on the leaves - Thanksgiving cacti leaves are more pointy on the edges, while the Christmas Cacti have more rounded leaves and bloom closer to Christmas.