Can I use a home oxygen machine especially for babies, my 3 wk old is congested.

No. Nasal congestion is not a reason for oxygen supplementation and it will not improve any symptoms of nasal congestion. In fact, these types of therapies tend to provide dry air and may make the symptoms of nasal congestion worse. If your baby is having problems with breathing, especially if they seem short of breath or unable to eat normally, you should discuss with your physician.