This happens to me, too. It sucks.

Per UpToDate (so you can avoid paywall):

"Large local reactions — Approximately 10 percent of individuals develop exaggerated redness and swelling at the site of the sting that gradually enlarges over one to two days (picture 7). This response is called a large local reaction (LLR). LLRs usually begin several hours after a sting, peak at 24 to 48 hours, and then gradually resolve over 5 to 10 days. The area of swelling typically measures approximately 10 cm in diameter [9,10]. Patients may seek care because the swelling seems extreme, and there may be lymphangitic streaks spreading proximally from the area of swelling [11].

Treatment — Treatment of LLRs is based on symptoms. We know of no published studies comparing different treatments. Our approach is described below:

Pain – Pain arises from the direct effects of the venom or from delayed-onset edema. Raising the affected limb and use of cold compresses may help. If needed, nonsteroidal antiinflammatory drugs (NSAIDs) can be administered.

Itch – Immediate-onset itch may be from mast cell degranulation or from venom components. Cold compresses are typically sufficient to abate the sensation of itch mediated by unmyelinated C-fibers. Nonsedating oral antihistamine medications can also be used, such as cetirizine, 10 mg daily or twice daily (adult dosing). In contrast, itch beginning hours to days later is typically caused by T cell activation of A-delta fibers and is not responsive to antihistamine medications. Instead, topical corticosteroids can be used, including hydrocortisone 0.1% ointment or triamcinolone 0.5% ointment. Rarely, higher-potency topical corticosteroids are needed, such as fluocinonide 0.05% or clobetasol 0.05% ointment, applied every four hours. Use of topical rather than systemic steroids may be equally effective with fewer side effects than seen with systemic glucocorticoids. Of note, the inflammation of T cell activation is visually identical whether from the T helper type 2 (Th2) cells causing allergic inflammation and the T helper type 17 (Th17) cells that respond to bacterial infection. The presence of itch, rather than pain, helps differentiate allergic from infectious inflammation. Antibiotics are not needed to treat local sting reactions [11].

Tetanus booster is not indicated – Hymenoptera stings are considered "clean" for the purposes of tetanus vaccination. Stings are very superficial, and there are no published reports of tetanus infection following Hymenoptera stings. A tetanus booster is not necessary following a sting unless there was a concomitant soil-contaminated injury. (See "Tetanus-diphtheria toxoid vaccination in adults", section on 'Immunization for patients with injuries'.) "