Chickenpox? ah! Can't get them?!

There's nothing you can do.
You've been exposed to the virus.
There is NO medication that will keep you from getting it, unless you were ever given the Chickenpox vaccine.
You almost certainly WILL get it, esp. since your immune system is permanently compromised by the eczema.
The good thing is humans usually only get it once, then are permanently immune.
There have been a few people that got it twice, but they are rarities.

Nurse

It really is impossible to say whether or not you will get them. You have been exposed to the virus and may have contracted it, assuming you haven't been vaccinated. (in the UK the chicken pox vaccine isn't routinely given)

It usually takes around 2-3 weeks from infection until you develop the rash, though it can be sooner, until then it really is just a waiting game. Teens and adults often experience aches, pains, nausea and headaches before the rash sets in though in children the rash is often the first sign.

Med Student

There is nothing definate, but you have a very good chance. Sorry, just go to the doctor now, maybe they can do soemthing to help.

my sister is immune to them but can carry them,
maybe you are a carrier also, and thats how your cousin got them
from you.

You will not definitely get them. If you're updated on your chicken pox shot, you should be absolutely fine. :)