Like slangevar said, they may never go down. Some people have permanately enlarged nodes (even big ones, like slangevar said as well). Over 2cm doesn't automatically equal cancer either, it just means the doc will take a closer look at them. Everyone's nodes are diff. Some can only be felt in certain positions, some can be felt by poking hard, soft, only on some days, etc.
My doctor said a noticeable infection doesn't have to be present for a node to swell. She said it can be something small that isn't showing symptoms. She also said it can be caused by dandruff, a scratch, a bug bite, etc. Some people's are more sensitive than others.
If you touch them, YOU WILL irritate them. And if you do, it will take longer to go down. People have said it can take 6 WEEKS for them to go down, sometimes longer, sometimes never. But you are doing more harm by constantly touching them.
The cold is enough by the way, to make one swell. Unless they were big, rock hard, immovable, painless and constantly growing significantly everyday, you're totally fine.
Didn't you also say your mom said you had it forever? if you've had it for years or even months and its been the same or smaller, then you really have ZERO REASON to worry. Seriously, some people I know have over 5 or 6 shoddy nodes that are "rock hard" and they have had them forever. No lymphoma.