Thanks for writing to us.
The bump developed at the hard palate may be due to-
Deep dental caries progressed into periapical abscess
Gingivitis lead into periodontal abscess
Removable dentures/orthodontic appliances inserted.
I would advice you to get clinical evaluation done by your dentist
to rule out the cause of bump arised.
The pus has to be drained and curetted.
Discontinue use of appliances/dentures if causing irritation.
Root canal treatment
has to be done if required.
Hope this helps.