Most of the lumps I have removed from tonsils have returned on excision biopsy as fibrous or chronically inflamed tonsillar tissue. Occasionally, it turns out to be viral warts. These are not dangerous lumps.
However, as your tonsil lump has been growing in size, and is also one sided, I would advise removal of the lump as we have no other way of excluding the low possibility of a cancer type of lump.
If you do not remove the lump, you need to monitor it very closely; my patients have found that more stressful than the removal of the lump in the longer term! Some removal can be in the clinic with you awake. However, if the lump is in a difficult to reach place of the tonsil or with a large base, a removal under a short anaesthetic may be better.
Kind regards,
Dr Lynne Lim