What should i do about allergic reaction to injections?

Depends: Depends both on the nature of the reaction and injection. Many infusion reactions are not due to a specific immune response, but to a poorly understood nonspecific activation of innate immunity (eg complement activation, cytokine release, or non-IgE basophil degranulation). In such cases, simply decreasing the infusion rate may help. Suggest virtual consult with Allergist to begin a discussion!