Dreams involving children, especially those depicting them as younger than they are, often reflect feelings of nostalgia, concern, or a desire to protect. Your son being a toddler in the dream may symbolize a longing for simpler times or a need to nurture and care for him in ways you feel are important.

The car accident can represent a fear of losing control or facing unexpected challenges in your life. It may also indicate anxiety about your son's well-being, especially if you've been feeling protective or worried about him lately. The sore part on your chest might signify emotional pain or distress related to these feelings, suggesting that you might be carrying a burden or concern regarding your son’s health or safety.

The doctor's visit and the swelling and rash on his face could symbolize your desire to seek help or reassurance in a situation you feel is out of your control. This part of the dream may indicate your concerns about potential problems that you want to address before they escalate.

Overall, this dream seems to reflect your deep care for your son and possibly some anxieties about his health and safety. It might be beneficial to take some time to reflect on any current stresses you are feeling and consider if there are ways to alleviate them, whether through open communication, seeking support, or taking proactive steps in your life.