u/Unhappy-Shopping-424

When I pick up my rat, or even when I put my hands in his cage so he can climb onto them, he often starts licking my hands once he's sitting on them.
I wanted to ask if this is normal behavior or if it could be a sign that he's uncomfortable. He never bites me or anything like that—he just licks my hands. Sometimes he also licks my nose.
Another thing he does is gently take one of my fingers in his mouth and then tries to "pull" my arm into the cage, as if he wants to lead me to his nest.
Is this normal? Does it mean that he feels safe and comfortable with me?

I adopted my rat two months ago, and he is almost 7 months old now. The reason I adopted him is because the place where he lived before was a completely empty glass tank with wood shavings, which were really bad for his respiratory system. On top of that, he is much smaller than the average rat. His vet jokingly called him a “dwarf rat.”

He has gained weight since then and is now at a very healthy weight, but what worries me the most is that he came to me with untreated respiratory issues. Of course, I took him to the vet from day one, and he was on medication for almost a month. He is also naturally very sensitive/allergic, and from time to time he still sneezes or makes small “eee/iii” noises when breathing, but they only last a few seconds.

I want to clarify that he is constantly monitored by his vets, and they have discharged him as a healthy rat, but with this respiratory issue that I am obviously very attentive to.

My question is: is there anything else I can do to improve his quality of life regarding his respiratory condition?

I clean his waste every day, since he uses a corner litter tray, so it is easy to keep clean. It is winter where I live right now, so I have different blankets on all four levels of his cage so he can stay warm. But, as expected, he sometimes pees on them, and I don’t leave them there for more than a day once they smell like urine because I know that can be bad for him. So I wash them constantly.

I recently ordered some absorbent blankets, and I hope they work well. But aside from that, is there any special food or anything I can give him to help support his immune system?

This is my first time being a rat owner, and I am honestly a bit scared all the time because I love him so much. Something that also breaks my heart is that, despite everything people usually recommend, I was told that it might be best not to get him a companion. He has always lived alone, so he might be territorial, and since he is such a small rat, if another rat attacked him or even defended itself, it could seriously hurt him because the difference in size and strength could be huge.

Like I said, he is almost 7 months old, and his healthy weight is still under 300 grams.

Again, sorry for the long post. I just really need advice on how to make sure he has the best life possible. Luckily, I work from home, and his cage is right next to my desk in my office, so I am always with him.