Mottemama,

Sulphur is the remedy par excellence for itchy eruptions that are aggravated by heat, esp. in the warmth of bed. Clarke says it's for "affections in general of any kind appearing on l. side; external front of head; inner belly, esp. l. side; back; and of the nails". And it is also a very warm remedy. But there are some other curious symptoms here. It's interesting that the eczema went away during the stomach flu and R. Murphy shows that Graphites is strongly indicated for 'eczema alternating with internal affections'. Although, it's not uncommon for eczema to be alleviated by deeper maladies (usually of the lungs), and my understanding is that Graphites is for eruptions that are moist and oozing, which you did not specify. The 'sneezing in sunlight' is also interesting but may not be terribly important. It could pertain to an underlying remedy.

I would be quite concerned about the possible link with the vaccination and seek to clear this up as soon as possible. These kinds of problems can linger and go deeper into the system if not treated properly.