Gynecomastia can be glandular and or fat. When it is fatty, liposuction removes the fat. When it is glandular you have extra breast gland which grows and is firm. This can cause protrusion of the nipple. It looks like you have a mild case, which can be treated surgically by removing part of the gland under the nipple. Thus will flatten the nipple and leave a small scar around the areola. Liposuction does not work for glandular gynecomastia.
Judging from your picture you seem to have puffy nipples ,which is gynecomastia
Judging from your picture you seem to have puffy nipples ,which is gynecomastia. Not always it is very hard ,and most are not sensitive.You should consult with an experienced gynecomastia surgeon.Unfortunately surgery is the only way to fix it.