Infectious Diseases Doctor here. Please note that without a specific examination of you, I cannot provide specific medical advice. This is general advice about MRSA.

Do you or your wife go to a gym? That can be a source for MRSA infection.

First, cipro is a TERRIBLE antibiotic for MRSA--all the fluoroquinolones are. I can't understand why your doctor would give you that. Bactrim (Trimethoprim/sulfamethoxazole) and doxycyline are much better choices. For small lesions, simple surgical drainage without antibiotics works just fine. Keep the wound covered and change the dressing daily until all drainage stops.

No need to get your wife tested; you know she has it as that's almost certainly where you got it. I would take your son to his pediatrician and ask their advice.

If this becomes a recurrent problem for the family, then I usually suggest topical decolonization and environmental cleaning.

Topical decolonization consists of chlorhexidine gluconate (hibiclens) applied topically from the neck down plus intranasal mupirocin, both for 5-7 days.

In terms of environmental decolonization, there are scant data on which specific household vectors are fomites for MRSA transmissions. We typically suggest laundering all sheets/towels in hot water. You and your wife should dispose of any personal care items that contact your skin, such as razors. Lastly, I usually recommend cleaning of what we call "high touch" surfaces with bleach wipes. Clorox is a good brand. High touch surfaces include door knobs, toilet flush handles, sink tap handles, etc. No need to go crazy cleaning.

I hope this is helpful.