After the fall we usually advise parents to watch for change in behaviour,vomiting
,abnormal movements like a convulsion
.Since your child had a vomit and now the swelling though the swelling seems to be external.Fall from 2 feet is slightly too high for a 7mths old.I guess it would be worthwhile to get CT Scan
Brain to rule out internal bleed like Sub dural hematomas ,fracture
etc.it would be better to get all the investigation done and admit to hospital for obsevation.