Fever due to breast engorgement tends to remain ≤ 39 ° C.
[msdmanuals.com]
Patients with low-grade fever and no abdominal pain are evaluated for other occult causes, such as atelectasis, breast engorgement, breast infection, UTI, and leg thrombophlebitis
[msdmanuals.com]
If temperature abruptly rises after 2 or 3 days of low-grade fever, the cause is probably an infection rather than breast engorgement.
[msdmanuals.com]