Thanks for posting your query.
The red bumps described by you could be urticaria
. As it is there for few months and disappears, I suggest that you need to undergo a battery of tests to find out the cause. The common causes which I could find in my practice are either a thyroid
problem or raised IgE levels. These could be tackled with appropriate drugs or modification of diet. You need to take anti histamines
in addition. The problem is only temporary and may vanish in few months with treatment and life style modification.