Esmeralda, it is nothing to worry about. Scrape the scale off. Some insect chewed the leaves a a while ago and I doubt that it is still around. You can kill whatever scale may be present by spraying with neem oil. Pretty soon you will not have insect problems when you take your tree outside.

You would not lose the tree if you prune the top but try not to remove too many leaves.

Neem oil did not prevent scale bugs on my tree.... So my advice is make sure u wipe off all scale bugs . Keep checking your tree for new ones.

Neem oil is better at killing nymphs and crawlers than adults, so it's helpful to apply oils every week or two (mind your sunshine and hot weather, though). If you only have a few trees, inspect them for the big insects (and manually kill them), and then spray them to kill the crawlers that we can't see.

-Tom