So, here is update. I do believe that both Degus are the same sex. I can't really tell on the younger on but I got a good look today. Pretty sure he is a she. Lucy is scratching a lot and I don't know what that means. I thought it was fleas till me fiance pointed out that Desi would be doing the same thing. So it can't be fleas. And how do we get Desi to be more social able? When we pet him he flees. Lucy, who was alone for 2 years without a degu, loves it and comes to the door when we walk by. Desi just tries to get out and run off. What do I do?
Just because the other degu isn't scratching doesn't mean much, it could mean that the other hasn't caught them yet. I doubt she has fleas but mites are a possibility, keep an eye out for increased scratching, bald ears, fur loss, etc. Scratching could also mean she needs a good dust bath and it could also be a symptom of allergies. What kind of bedding do you use?
Try letting them both out in a small, enclosed area. Let Desi come to you on her own terms, don't try to pick her up or anything. Offer her small treats and let her climb on you. As she gets more comfortable, you can try petting her gently